Manager User

create user test1 identified by test1;
grant connect,create table to test1;
conn cyts_cc/cyts_cc@orcl2000;
create table(
id int)
tablespace user;
ERROR 位于第 1 行:
ORA-01950: 表空间'USERS'中无权限
conn cyts_cc/cyts_cc@orcl2000;
alter user test1 quota 1M on users;
create tab
(id int);
success
alter user test1 account lock;
conn test1/test1@orcl2000;
ERROR:
ORA-28000: the account is locked
1 Database Schema
 a schema is a named collection of objects
 b user is created and a corresponding schema is created
 c user can be associated only with one schema
 d username and schema are often userd interchangely.
2 Checklist for creating users
  a idntfigy tablespaces in which the usr nedds to store objects
  b decide on quotas for each tablespace
  c assign a default tablespace and temporary tablespace.if you do not specify at the time of create user,system tablespace will be the defalut tablespace and temporary.it will affect the performance of the oralce.
  d create user
  e grant privileges and roles to user
  desc dba_users;
  select * from dba_users;
3 Creating a new user:
Database Authentiacation
 set the initial password
  create user aaron
  identified by soccer
  default tablespace data
  temporary tablespace temp
  guota 15m on data
  password expire;

  alter database default temporary tablespace temp;
4 Creating a new user operating System Authentication
  os_authent_prefix initialllization parameter specifies the format of the username
  defauts to ops$
    create user arron
    identified externally
    default tablespace users
    temporary tablespace temp
    quota 15m on data
    password expire;

    conn /
    show parameter os
    os_authent_prefix                    string                           OPS$
    create user ops$test3
      identified externally
      default tablespace us
      temporary tablespace
      quota 10m on users
    thee test2 is an user of os ,which the oracle is installed.
5 Changing user quota on tablespace
 alter user test3 quota 4m on users;
 you cann't grant quota on temp and undotbs.
 
 alter quota 0 on uers -- means that no new table space can be allocated and cannot change the exist object in the tablespaces
6 drop user
 you cannot drop user who has connected to oracle
  drop user (cascade)
7 Obtaining User information
 information about uers can be obtained by qerying the data dictionary
  dba_users
  名称                          
-----------------------------
USERNAME                      
USER_ID                       
PASSWORD                      
ACCOUNT_STATUS                
LOCK_DATE                     
EXPIRY_DATE                   
DEFAULT_TABLESPACE            
TEMPORARY_TABLESPACE          
CREATED                       
PROFILE                       
INITIAL_RSRC_CONSUMER_GROUP   
EXTERNAL_NAME                 
  dba_ts_quotas
   名称          
 ---------------
 TABLESPACE_NAME
 USERNAME      
 BYTES         
 MAX_BYTES     
 BLOCKS        
 MAX_BLOCKS    

posted @ 2006-10-12 09:49 康文 阅读(381) | 评论 (0) | 编辑 收藏

Using SET Operators.

1 The Union Operator
 The union operator returns results form both queries after eliminating duplications.\
 select employee_id,job_id
 from employees
 uniion
 select employ_id ,job_id
 from job_history;
2 the all operator
 The union all opertor reutrn result from both queries,including all duplications
3 interset
 select ster_id,qty from sales where qty>20;
 intersect
 select ster_id,qty from sales where ster_id like '7%';
4 minus
 select ster_id,qty from sales where qty>20
 minus
 select ster_id from sales where ster_id like '7%'

5 set operator guidelines
 . teh expressions in the select list must match in number and data type;
 . Parentheses can be used to alter the sequence of the execution
 .The order by clause:
    can appear only at the very end of the statement
    will accept the column name,aliases from thee firest select statement ,or thee positional notation
 .Duplicate row are atuomatically eliminated except in union all.
 .Column names from the first query appear in the result
 .The output is sorted in ascending order by default except in union all
6 matching the select statement
 select department_id,to_number(null),location,hire_date
 from employees
 union
 select department_id,location_id,to_date(null)
 from departments;

 select employee_id,job_id,salary
 from employees
 union
 select employee_id,job_id,0
 from job_history;
7 Controlling the order of the rows
 select 'sing' as "my dream" ,3,a_dummy
 from dual
 union
 select 'like''d like to teach',1
 from dual
 union
 select 'the world to',2
 from dual
 order by 2;

posted @ 2006-10-11 14:51 康文 阅读(217) | 评论 (0) | 编辑 收藏

开发子过程

 1  开发过程
 1) 建立过程：不带参数
  create or replace procedure out_time
  is
  begin
    dbms_output.put_line(systimestamp);
  end;
  a 使用execute 命令调用过程
   set  serveroutput on
   exec out_time;
  b 使用call 命令调用过程
   set serveroutput on
   call out_time();
 2) 建立过程：带有in参数 默认为输入参数，另外也可以使用in 关键子显示的定义
   create or replace procedure add_employee
   (eno number,name varchar2,sal number,
    job varchar default 'clerk',dno number)
   is
   e_integrity exception;
   pragma exception_init(e_intgegrity,-2291);
   begin
    insert into emp(empno,ename,sal,job.deptno)
      values(eno.name,sal,job,dno);
    exception
      when dup_val_on_index then
        raise_application_error(-20000,'雇员号不能重复');
      when e_integrity then
        raise_application_error(-20001,'部门号不存在');
   
调用
   exec add_employee(111,'clark',200,'manager',10);
   3 建立过程，带有out 参数
    create or replcace procedure query_employee
    (eno number,name out varchar2,salary out number)
    is
    begin
      select ename,sal,into name,salary from emp where empno=eno;
    exception
      when no_data_found then
        raise_application_error(-20000,'G该雇员不存在');
    end;
   
    调用
    var name varchar2(10)
    var salary number
    exec query_employee(7788,:name,:salary);
    print name,salary;
    4 建立过程，带有in out 参数
    create or replace procedure compute
    (num1,in out number,num2 in out number)
    is
       v1 number;
       v2 number;
    begin
      v1:=num1/num2;
      v2:=mod(num1,num2);
      num1:=v1;
      num2:=v2;
    end; 
   
    调用
    var n1 number
    var n2 number
    exec :n1:=100;
    exec :n2:=30
    exec compute(:n1,:n2)
    print n1 n2
    5) 为参数传递变量和数据 位置传递，名称传递，组合传递
    create or replace procedure add_dept
    (dno number,dname varchar2 default null,loc varchar default null)
    is
    begin
      insert into dept values(dno.dname,loc);
    end;
    -- 位置传递
     exec add_dept(50,'sales','new york');
     exec add_dept(60);
     exec add_dept(70,'admin');
    -- 名称传递
     exec add_dept(50,loc=>'new york');
     exec add_dept(60,dname=>'sales',loc=>'new york');
   6) 显示当前用户的所有程序及其源代码
     select text from user_source where name='add_dept';
   7) 删除过程
     drop procedure add_dept;
2 开发函数
  可以在sql语句和其他子过程中执行。
  1 建立函数，不带任何参数
  create or replace function get_user
  return varchar2
  is
    v_user varchar2(100);
  begin
    select username into v_user from user_users;
    return v_user;
    end;
  --使用变量接收函数返回值
   var v2 varchar2(100)
   exec :v1:=get_user
   print v1;
 -- 在sql 语句中直接调用函数
   select get_user from dual;
 -- 使用dbms_output 调用函数
   set serveroutput on
   exec dbms_output.put_line('get_user');
 2) 建立函数，带有in 参数
   create or replace function get_sal(name in varchar2)
   reutnr number
   as
   v_sal emp.sal%type;
   begin
     select sal into v_sal from emp where upper(ename)=upper(name);
     return v_sal;
   exception
     when no_data_found then
       raise_application_error(-20000,'employee does not exist');
   end;
 3) 建立函数，带有out 参数
   create or replace function get_info
   (name varchar2,title out varchar2)
   return varchar2
   as
     deptname dept.dname%type;
   begin
     select a,job,b,dname into title,deptname from emp a,dept b
     where a.deptno=b.deptno
     and upper(a.ename)=uppder(name);
     return deptname;
   end;
   var job varchar2(20)
   var dname varchar2(20)
   exec :dname:=get_info('scott',job);
   print dname job

 4) 带有 in out 参数
  create or replace function result
  (num1,number,num2 in out nu8mber)
  return number
  as
    v_result number(6);
    v_remainder number;
  begin
    v_result:=num1/num2;
    v_remainder:=mod(num1,num2);
    num2:=v_remainder;
    retrun v_result;
  exception
    when zero_divide then
       raise_application_error(-20000,'zero divied');
  end;
 5) 函数调用的限制
  -- 在sql 语句中只能调用存储函数
  -- 在sql 语句中只能调用带有输入参数in ，而不能有输出参数out 和in out 参数的函数
  -- 在sql 语句中调用的函数的参数必须是标准的sql 数据类型，不能是pl/sql 所特有的数据类型
  -- 在sql 语句中调用的函数不能包含insert，update 和delete
 6) 查看源代码
  set pagesize 40
  select text form user_source where name='result';
 7) 删除函数
  drop function result;
 3 管理子程序
  1) 列出当前用户的子程序
   select object_name,created,status form user_objects
   where object_type in ('procedure','function');
  2)列出子程序源代码
   select text from user_sorce where name='raise_salary'
  3)类出子程序编译错误
    -- show errors
    --使用数据字典user_errors  确定错误原因和位置
     select line||'/'||position as "line/col",text error
     from user_errors where name='raise_salary';
   4) 列出对象的依赖关系
    -- 使用 user_dependenciess 确定直接依赖关系
    select name,type from user_dependencies
    where referenced_name='emp'
    -- 使用 deptree 和 ideptree 确定依赖和见解依赖关系
    select nested_level,name,type from deptree;
   5) 重新编译子程序
     当被应用对象的结构被修改以后，就会将相关依赖对象转变为无效invalid ，需要重新编译
     1
     alter table emp add remark varchar2(100);
     2
     select object_name,object_type from user_objects
     where status='invalid'
     3
     alter procedure add_employee compile;
     alter view dept10 compile;
     alter function get_info compile;
     
  

posted @ 2006-10-11 14:51 康文 阅读(284) | 评论 (0) | 编辑 收藏

处理例外

1例外简介
 1） 例外分类
  预定义分类，非预定义分类，自定义例外。
2 处理预定义例外
  1) 常用预定义例外
   a access_into_null;
     create type emp_type as object
     (name varchar2(2),sal number(6,2));
    
     declare
       emp emp_type;
     begin
       emp.name:='scott';
     exception
       when access_into_null then
          dbms_output.put_line('首先初始化对象emp');
    b case_not_found
     undef no
     declare
       v_val emp.sal%type;
     begin
       select sal into v_sal from emp where empno=&no;
       case
         when v_sal<1000 then
           update emp set sal=sal+100 where empno=&no;
         when v_sal<2000 then
           update emp set sal=sal+150 where empno=&no;
         when v_sal<3000 then
          update emp set sal=sal+200 where empno=&no;
       end case;
       exception
         when case_not_found then
           dbms_output.put_line();
      end;
    c collection is null
    在给集合元素（嵌套表或array类型）赋值前，必须首先初始化集合元素
    declare type ename_table_type is table of emp.eanme%type;
    ename_table ename_table_type;
    begin
      select e_name into ename_talbe(2) from emp where empno=$no;
    exception
      when collection_is_null then
        dbms_output.put_lilne('必须使用构造方法初始化集合元素');
    end;
    d currsor_already_open
    reopen curosr 如果用户已经使用了open 命令打开了显示游标，或执行for循环(隐式的打开游标)
       delcare
         cursor emp_surosr is select ename,sal,from emp;
       begin
         open emp_curosr;
         for emp_record in emp_cursor loop
              dbms_output.put_line(emp_record.eanme);
         end loop;
       exception
          when cursor_already_open then
            dbms_output.put_line("游标已经打开");
       end;
     e dup_val_on_index
     begin
     exception
        when dup_val_on_index then
        dbms_output.put_line("列上不能出现重复值");
     end;
     d invalid_curosr
     delcare
       curosr emp_cursor is select ename,sla from emp;
       emp_record emp_crusor%rowtype;
     begin
       fetch emp_cursor into emp_record;
       close emp_crusro;
     exception
       dbms_output.put_line("游标没有打开");
     end;
     f invalid_number  can not convert char to nmuber successfully
       begin
         update mep set sal=sal+1oo;
       exception
         when invalid_number then
     g no_data_found  when select into is executed ,no row is returned     
       declare
         v_sal emp.sal%type;
       begin
          select sal into v_cal form emp where lower(ename)=lower('&name');
       exception
         when no_data_found then
             dbms_output.put_line('没有返回结果');
       end;
      h too_many_row  ora -01422 there are too many are return when "select into" is executed
      i zero_divide ora-01476
      g subscript_beyond_count ora-065533
      declare
        type emp_array_type is varray(20) of varchar2(10);
        emp_array emp_array_type;
      begin
         emp_array:=emp_array_type('scott','mary');
         dbms_output.put_line('emp_array(3)');
      exception
         when subscript_beyone_count then
          dbms_out.put_line('超出下标范围');
      end;
      k subscript_outside_limit
       emp_array(-1);
      l value_error the length of variable cannot contain the actual value;
      declare
      begin
      end;
3 处理非预定义例外
  delcare
    e_integrity exception;
    pragma exception_init(e_integrity,-2291);
  begin
    update emp set deptno=dno where empno=&no;
  exception
    when a_integrity then
  end;
4 处理自定义例外
  与oracle 错误没有任何联系，为业务逻辑所定义的例外
  delcare
    e_no_employee exception;
  begin
    update emp set deptno=&dno where empno=&eno;
  if sql%notfound then
    raise e_no_employee;
  end if;
  exception
    when e_no_emplyee then
     dbms_output.put_line('该雇员不存在');
5 使用错误例外函数
  使用例外函数可以取得错误号以及相关的错误消息，sqlcode 用于取得oracle 的错误号，而sqlerrm
则用于取得与之相关的错误信息。
  1 sqlcode 和 sqlerrm
  为了在pl/sql 应用程序中处理其他为预料的到的oracle 错误，用户可以在例外处理部分的
when others 自句后，引用两个函数
  declare
    v_ename emp.ename%type;
  begin
    select ename into v_ename form emp where sal='&v_sal';
  exception
    when no_data_found then
    when others then
       dbms_output.put_line(sqlcode);
       dbms_output.put_line(sqlerrm);
  end;
  2 raise_aaplicaition_error
   只能在子程序中使用（过程，函数，包，触发器）
   raise_application_error(error_number,message,[true|false]);
   error_number 错误号，在－20000到－20999 之间
   message 指定错误消息，不能超过2048 
   if v_comm is null then
       raise_application_error(-20001,'该雇员无补助');
   end if;

posted @ 2006-10-11 14:46 康文 阅读(290) | 评论 (0) | 编辑 收藏

开发包

posted @ 2006-10-11 14:46 康文 阅读(352) | 评论 (0) | 编辑 收藏

including Constraints

posted @ 2006-10-11 14:45 康文 阅读(231) | 评论 (0) | 编辑 收藏

create view

posted @ 2006-10-11 14:45 康文 阅读(292) | 评论 (0) | 编辑 收藏

使用触发器

1 触发器简介
  1) 触发事件
  2) 触发条件
  3) 触发操作
     . 触发器代码的大小不能超过32k，如果使用大量代码建立触发器，应该先建立存储过程，然后再触发器中使用call语句调用存储过程。
     . 触发器中正能含有select ，insert，update 和delete 语句，而不能含有ddl 语句，和事物控制语句。
2 建立dml 触发器
 1) 触发时机
  before，after 表示在执行dml操作之后触发器
 2)触发事件
  insert ，update 和delete 操作。也可以使用书法事件
 3) dml 触发器是针对特定表进行的 因此必须制定dml 操作所对应的表
 4) 触发器类型 用于指定当触发器事件之后，需要执行几次触发器操作。如果指定语句触发器类型
那么会执行一次触发器代码：如果指定行触发器类型，则会在每个被作用行上执行一次触发器代码。
 5) 触发条件
 用于指定执行行触发器代码的条件，只有为ture时，才会执行行触发器代码。
  6) 如果使用pl/sql 存储过程，java 存储过程，或外部处处过程需要在触发器操作部分直接使用call
  7) dml 触发器触发顺序
   (1)dml 触发器在单行数据上的触发顺序。
    对于单行数据而言，无论是语句此触发器，还是行触发器，触发器代码实际只执行一次，并且执行
顺序为before 语句触发器，before 行触发器，dml 操作，after 行触发器，after 语句触发器
   (2) dml 触发器在多行数据上的触发顺序
    before 语句触发器
    before 行触发器
    after 行触发器
    before行触发器
    after 行触发器
    after语句触发器
   语句触发器只被执行一次，而行触发器在每个行上都执行一次。
  2) 语句触发器
  当审计dml 操作，或确保dml操作安全执行时，可以使用语句触发器
  1 建立before 语句触发器
   create or replace trigger tr_sec_emp
   before insert or update or delete on emp
   begin
     if to_char(sysdate,'DY','nls_dtate_language=AMERICAN') in ('sat','sun') then
     railse_application_error(-200001,'不能在休息日改变雇员信息');
     end if;
   end; 
   2 使用条件谓词
   inserting ,updating ,deleting
   create or replace trigger tr_sec_emp
   before insert or update or delete on emp
   begin
     if to_char(sysdate,'DY','nls_date_language=american')
      in('sat','sun') then
     case
       when inserting then
         raise_application('-20001','inserting');
       when updating then
         raise_application('-20002','updating');
       when deleting then
         raise_application('-20003','deleting');
     end case;
    end if;
   end;
   3 建立after 语句触发器
    为了dml 操作，或者dml 操作后执行汇总运算
   create table aduit_table(
     name varchar2(20),ins int,upd int,del int,
     starttime date,endtime date
   );
   create or replace trigger tr_aduit_emp
   after insert or update or delete emp
   declare
     v_temp int;
   begin
     select count(*) into v_temp from aduit_table
       where name='emp';
     if v_temp=0 then
       insert into audit_table values
       ('emp',0,0,0,sysdate,null);
     end if;
     case
       when  inserting then
         update aduit_table set ins=ins+1,endtime=sysdate where name='emp';
       when updating then
         update audit_table set upd=upd+1,endtime=sysdate where name='emp';
       when deleting then
         update aduit_table set del=del+1,endtime=sysdate where name='emp';
   end;
  3) 行触发器
   审计数据变化可以使用行触发器
   1 建立不before 行触发器
    为了取保数据符合商业逻辑或企业规则，对输入的数据进行复杂的约束，可以使用before行触发器
     create or replace trigger tr_emp_sal
     before update of sal on emp
     for each row
     begin
       if :new.sal<:old.sla then
         raisse_application_error(-200010,'工资只涨不降');
       end if；
     end;
     2) 建立after 行触发器
     为了审计dml 操作，可以使用语句触发器或oracle 系统提供的审计功能，而为了审计数据变化
，则应该使用after 行触发器
     create table audit_emp_change(
       name varchar2(10),odl number(6,2),
       newsal number(6,2),time date);
    create or replace trigger tr_sal_change
    after update of sal on emp
    for each row
    declare
     v_temp int;
    begin
     select count(*) into v_temp from audit_emp_change where name=:old.ename;
    if v_temp =0 then
      insert into audit_emp_change
        values(:old,ename,:old.sal,:new,sal,sysdate);
    else
      update audit_emp_change
        set oldsal=:old.sal,newsal=:new.sal,time=sysdate where name=:old.ename; 
    end if;

    end;
     )
    3) 限制行触发器
    当使用行触发器，默认情况下会咱每个被作用行上七星一次触发器代码，为了时得再特定条件下执行行触发器代码，需要使用when 子句
    create or replace trigger tr_sal_change
    after update of sal on emp
    for each row
    when(old.job='salesman')
    declare
       v_temp int..
2 dml 触发器使用注意事项
  触发器代码不能从触发器所对应的基表中读取数据
3 dml 触发器
  为了保证数据库满足特定的商业规则或企业逻辑，可以使用约束，触发器和子程序。约束性能最好，实现最简单，所以为售选，如果触发器不盟实现，可以选择触发器。
  dml 触发器可以用于实现数据安全保护，数据审计，数据完整性，参照完整性，数据复制等功能。
 1) 控制数据安全
  create or replace trigger tr_emp_time
  before insert or update or delete on emp
  begin
    if to_char(sysdate,'hh24') not between '9' and '17' then
      raise_application_error(-20101,'not work time');
     end if;
  end;
  2) 实现数据审计
  使用数据审计只能审计sql 操作，而不会记载数据变化
  audit insert,update,delete on emp by access
  3)实现数据完整性
  首选约束 alter table emp add constraint ck_sal check (sal>=800),但是在有些情况下只能使用触发器来实现数据完整性
   create or replace trigger tr_check sal
   before update of sal on emp
   for each row
   when (new.sla<old.sal or new.sal>1.2* old.sal)
   begin
      raise_application_error(,,,,,,)
   end;
  3) 使用引用完整性
  采用 on delete cascade 可以进行集联删除，但是却不能进行集联更新。采用触发器实现集联更新
   create or replace trigger tr_update
   after update of sal on emp
   for each row
   begin
     update emp set depno=:new.deptno where dentno=:old.deptno;
   end;
4 建立instead of 触发器
  对于简单视图可以直接进行insert update 和delete 等操作，但是对于复杂视图不允许进行insert，update 和delete 操作。
  满足一下条件的为复杂视图
    具有操作集合符 union，union all ，intersect，minus
    具有分组函数 min，max，avg，sum，count
    具有group by connect 编译 或start with
    具有distinct
    具有连接
  为了在复杂视图上执行dml 操作，必须要基于instead-of 触发器，建立instead－of 触发器后，就可以基于复杂视图执行insert，update和delete 语句。
   instead of 选项只使用于视图
   基于视图建立触发器时，不能定义before 和 after
   在建立视图时不能指定 with check option
   当建立instead of 触发器时，必须指定for each row 选项
  1) 建立复杂视图dept_emp
   create or replace view dept_emp as
   select a.deptno,a.dname,b,empno,b,ename
   from dept a,emp b
   where a,deptno=b.deptno;
  2) 建立 instead－of 触发器
   create of replacee trigger tr_instead_of_dept_emp
   instead of insert on dept_emp
   for each row
   declare
     v_temp int;
   beegin
      select count(*) into v_temp from dept where deptno=:new.deptno;
      if v_temp=0 then
        insert into dept(deptno,dname) values(:new.deptno,:new.dname);
      end if;
      select count(*)into v_temp from emp where empno=:new.empno;
      if v_temp=0 then
         insert into emp(empno,ename,deptno)
           values(:new.deptno,:new.ename,:new.deptno);
         end if;
   end;
  
   可以对视图执行insert 操作了
    insert into dept_emp values(50,'admin','1223','mary')
5 管理触发器
  1) 显示触发器信息
    select trigger_name,status from user_triggers
    where table_name='emp';
   2)禁止触发器
    alter trigger tr_check_sal disable;
   3) 激活触发器
    alter trigger tr_check_sal enable;
   4) 禁止或激活表上的所有触发器
    alter table emp disable all triggers;
    alter table emo eanble all triggers; 
   5)重新编译触发器
    alter trigger tr_check_sal compile;
   6) 删除触发器
    drop trigger tr_check_sal;

posted @ 2006-10-11 14:44 康文 阅读(1013) | 评论 (0) | 编辑 收藏

使用复合变量

posted @ 2006-10-11 14:44 康文 阅读(335) | 评论 (0) | 编辑 收藏

advanced subquery

posted @ 2006-10-11 14:43 康文 阅读(253) | 评论 (0) | 编辑 收藏

开发动态sql

1 动态sql 简介
2
  1 使用execute immediate 处理ddl 操作
    create or replacee procedure drop_table(table_name varchar2)
    is
     sql_statement varchar2(100);
    begin
       sql_statement:='drop table'||table_name;
       execute immediate sql_statement;
   调用
       exec drop_table('worker');
    end;
    2) 使用 execute immediate 处理dcl 操作
    create or replace procedure grant_sys_priv
    (priv varchar2,username varchar2)
    is
    begin
     sql_stat:='gruant'||priv||'to'||username;
     execute immediate sql_stat;
    end;

   exec grant_sys_priv('create session','scott');
   3 使用execute immediate 处理dml 操作
     1) 处理无占位符和returning 子句的dml 语句
     delcare
      sql_stat varchar2(100);
     begin
      sql_stat:='update emp set sal=sal*1.1 where deptno=44';
      execute immediate sql_stat;
     end;
      2) 处理包含占位符的dml语句
       delare
        sql_stat varchar2(100);
       begin
         sql_stat:='update emp set sql=sql*(1+:percent/100)'
                 ||'where deptno=:dno';
         execute immediate sql_stat using &1,&2;
       end;
      3) 处理包含returning 子句的dml语句
       declare
         salary number(6,2);
         sql_stat varchar2(200);
       begin
         sql_stat:='update emp set sal=sal*(1:percent/100)'
            ||'where empno=:eno returning sal into :salary';
         execute immediate sql_stat using &1,&2;
            returning into salary;
       end;
       输入1的值 15
       输入2的值 2222
       新工资；2223
      4) 使用execute immediate 处理单行查询
        declare
          sql_stat varcchar2(100);
          emp_record emp%rowtype;
        begin
          sql_stat:='select * from emp where empno=:eno';
          execute immediate sql_stat into emp_record using &1;
       end;
 3 处理多行查询语句
   declare
      type empcurtyp is ref cursor;
      emp_cv empcurtyp;
      emp record emp%rowtype;
      sql_stat varchar2(100);
   begin
      sql_stat:='select * from em where deptno=:dno';
      open emp_cv for sql_stat using &dno;
      loop
         fetch emp_cu into emp_record;
         exit when emp_cv%notfound;
      end loop;
      close emp_cv;
   end;
4 在动态sql 中使用bulk语句
   1) 在 execute immediate 语句中使用动态bulk 语句
     declare
       type ename_table_type is table of emp.ename%type
        index by binary_integer;
       type sal_table_type is table of emp.sal%type
        index by binary_integer;
       ename_table ename_table_type;
       sa_table sal_table_type;
       sal_stat varchar2(100);
       begin
         sql_stat:='update emp set sal=sal*(1+:percent/100)'
           || 'where deptno=:dno'
           ||'returning ename,sal into :name,:salary';
       execut immediate sql_stat using &percent,&dno
         returning bulk collect into ename_table,sal_table;
       for i in 1..ename_table.count loop
       ....
       end loop;
     end;
    2) 使用bulk 子句处理多行查询
      sql_stat:='select ename from emp where deptno=:dno';
      execute immediate sql_stat bulk collect into ename_table using &dno;
    3) 在fetch 语句中使用bulk 子句
      declare
        type empcurtyp is ref cursor;
        emp_cv empcurtyp;
        type ename_table_type is table of emp.ename%type;
         index by binary_integer;
        ename_table ename_table_type;
        sql_stat varchar2(100);
       begin
         sql_stat:='select ename from emp where job:=title';
         open emp_cv for sql_stat using '&job';
         fetch emp_cv bulk collect into ename_table;
    4) 在forall 语句中使用bulk 子句
      declare
        type ename_table_type is table of emp.ename%type;
        type sla_table_type is table of emp.sal%type;
        ename_table ename_table_type;
        sal_table sal_table_type;
        sql_stat varchar2(100);
      begin
        ename_table:=ename_table_type('scott','smith','clark');
        sql_stat:='update emp set sal=sal*1.1 where ename=:1'
            ||'returning sal into :2';
        forall i in 1..ename_table.count
          execite immediate sql_stat using ename_table(i)
            returning bulk collect into sal_table;       
      end;

posted @ 2006-10-11 14:43 康文 阅读(472) | 评论 (0) | 编辑 收藏

managing an oracle instance

posted @ 2006-10-11 14:42 康文 阅读(348) | 评论 (0) | 编辑 收藏

archetecture query

1 hierachical Queries
 select [level],colun,expr......
 from table
 [where condition(s)]
 [start with condition(s)]
 [connect by prior condition(s)]
 
 where condition
  exprcompparison_operator expr

2 Starting Point
 .Specifies the condition that must be met
 .Accepts any valid condition
3 Waling the Tree
  connect by prior column1=column2
  walk from the top donw ,using the employees table
   top donw
     column1=parentkey
     column2=childkey
   bottom up
     column1=child key
     column2=parent key

  select level,last_name
  from employees
  start with last_name='king'
  connect by prior employee_id=manager_id;

posted @ 2006-10-11 14:42 康文 阅读(182) | 评论 (0) | 编辑 收藏

extension to dml in oracle

posted @ 2006-10-11 14:41 康文 阅读(194) | 评论 (0) | 编辑 收藏

Managing Passswordd Security and Resources

1 Profiles
  1)a profile is a named set of password and resource limits
  2)Profiles are assigned to user by the create user or alter user command
  3)can be enable or disable
  4)can relate to the default profile.
2 Password Management
  Password history,account locking,password expiration and aging ,password verificcation.
3Enabling Password Management
  1)set up passwordd management by using profiles and assign them to users
  2)lock unlock and expire accounts usign the create user or alter user
  3)alwarys enforcing
   e.g
   create user test identified by test;
   alter user test account lock;
   alter user test account unlock;
   alteer user test password expire;
4 Passowrd Account locking
  FAIKED_LOGIN_ATTEMPS: number of failed login attemts before lockout of the account
  PASSWORD_LOCK_TIME : number of days the account is locked after the specified number of                        failed login attemps
  e.g
  create profile profile1 limit
  password_lock_time 1/1440  -- one muinuts
  failed_login_attempts 3;
 
  alter user test
  profile profile1;

  alter profile profile1 limit
  passowrd_lock_time 1/24  --one hour
5 passowrd expiration and aging
 passwowd_life_time lifetime of the passowrd in days  after which the password expires(有效期)
 password_grace_time grace period in days for changing the password after the first                      successful login afteer the password has expired(锁定期)
 e.g
 alter profile profile1 limit
 password_life_time 2
 password_grace_time 3;
6 password history
 password_reuse_time:number of days before a passowrd and be resued
 password _reuse_max:maxum number of times password can bee reused
 e.g
 alter profile profile1 limit
 password_reuse_time 10
 password_reuse_max 3;
7passowrd Verification(study latter)
8drop a profile
 drop profile profile1 (cascade);
the user will use the default profile.it will take effect on the new session.
9 Resource Management
 Resource mangement limits can be enforced at the session level,the call level or both
 limits can be defined by profiles using the create profile command
 enable resource limints with the
  .resource_limit initialization parameter
   alter system command
 e.g
 alter system set resource_limit=true;
10 setting a Resdource limits at session level
  cup_per_session : total cpu time measured in hundredths of seconds (百分之一秒)
  sessions_per_user: number of coucurrent sessions allowed for each username
  connect_time:elapsed connect time measured in minutes
  idle_time :periods of inactive time measured in minutes
  logical_reads_per_session: number of data blocks
  private_sga :measure in reads
  e.g
  alter profile profile1 limit
  cpu_per_session 100000
  connect_time 60
  idle_time 5;
 
  alter user test profile profile1

11 Setting Resource limits at call level 
 e.g
 alter profile profile1
 cpu_per_call 1000  -- cup time per call in
 logical_reads_per_call --number of data balock that can be read per call
 
  create profile develper_prof limit
   session_per_user2
   cpu_per_session 10000
   idle_time 60
   connect_time 480
12 Managing Resources using database resource manager
   1)Provides the oracle server with more control over resorce management decisions
   2)elements of database resorcee manager
    resource consumer group
    resourcee plan
    resource allocation method
    resource plan directives
   3)dbms_resource_manager package is uerd to create and maintain elements
   4)requires administer_resource_manager privilege
    desc dbms_resoource_manager
13 0btaining password and resource limits informaiton
  information about password and resource limits can be obtained by querying the data dictonary
   dba_users
   select * from users;
   dba_profiles
   select * from dba_profiles where profile='PROFILE1'

posted @ 2006-10-11 14:41 康文 阅读(205) | 评论 (0) | 编辑 收藏

jdbc-batch processing

the addBatch() method is basically nothing more than a tool fro assigning a bunch of sql statements to a jdbc statement object for execution together

PreparedStatement stmt=conn.prepareStatement(
      "update account set balance=? where acct_id=?");
int[] rows;
for(int i=0;i<accts.length;i++){
    stmt.setInt(1,i);
    stmt.setLong(2,i);
    stmt.addBatch();
  }
rows=stemt.executeBatch();

posted @ 2006-10-11 14:40 康文 阅读(206) | 评论 (0) | 编辑 收藏

翻页的实现

1 oracle 的实现
 语句一
SELECT ID, [FIELD_NAME,...] FROM TABLE_NAME WHERE ID IN ( SELECT ID FROM (SELECT ROWNUM AS NUMROW, ID FROM TABLE_NAME WHERE 条件1 ORDER BY 条件2) WHERE NUMROW > 80 AND NUMROW < 100 ) ORDER BY 条件3;
语句二：
SELECT * FROM (( SELECT ROWNUM AS NUMROW, c.* from (select [FIELD_NAME,...] FROM TABLE_NAME WHERE 条件1 ORDER BY 条件2) c) WHERE NUMROW > 80 AND NUMROW < 100 ) ORDER BY 条件3;

select * from (select rownum as numrow from table_name where numrow>80 and numrow<100 )
不能直接使用 select * from rownum>100 and rownum<200;
in oracle return null;
2 sql server 的实现
3 mysql 的实现

select id from table_name where id in
                                   select * from (select rownum as numrow ,id from tabl_name)
                                             where numrow>80 and num<100;                                           
                                                

posted @ 2006-10-11 14:39 康文 阅读(185) | 评论 (0) | 编辑 收藏

jdbc-prepare sql

posted @ 2006-10-11 14:38 康文 阅读(374) | 评论 (0) | 编辑 收藏

java 调用存储过程 转载

本文阐述了怎么使用DBMS存储过程。我阐述了使用存储过程的基本的和高级特性，比如返回ResultSet。本文假设你对DBMS和JDBC已经非常熟悉，也假设你能够毫无障碍地阅读其它语言写成的代码（即不是Java的语言），但是，并不要求你有任何存储过程的编程经历。
存储过程是指保存在数据库并在数据库端执行的程序。你可以使用特殊的语法在Java类中调用存储过程。在调用时，存储过程的名称及指定的参数通过JDBC连接发送给DBMS，执行存储过程并通过连接（如果有）返回结果。
使用存储过程拥有和使用基于EJB或CORBA这样的应用服务器一样的好处。区别是存储过程可以从很多流行的DBMS中免费使用，而应用服务器大都非常昂贵。这并不只是许可证费用的问题。使用应用服务器所需要花费的管理、编写代码的费用，以及客户程序所增加的复杂性，都可以通过DBMS中的存储过程所整个地替代。
你可以使用Java，Python，Perl或C编写存储过程，但是通常使用你的DBMS所指定的特定语言。Oracle使用PL/SQL，PostgreSQL使用pl/pgsql，DB2使用Procedural SQL。这些语言都非常相似。在它们之间移植存储过程并不比在Sun的EJB规范不同实现版本之间移植Session Bean困难。并且，存储过程是为嵌入SQL所设计，这使得它们比Java或C等语言更加友好地方式表达数据库的机制。
因为存储过程运行在DBMS自身，这可以帮助减少应用程序中的等待时间。不是在Java代码中执行4个或5个SQL语句，而只需要在服务器端执行1个存储过程。网络上的数据往返次数的减少可以戏剧性地优化性能。

使用存储过程

简单的老的JDBC通过CallableStatement类支持存储过程的调用。该类实际上是PreparedStatement的一个子类。假设我们有一个poets数据库。数据库中有一个设置诗人逝世年龄的存储过程。下面是对老酒鬼Dylan Thomas（old soak Dylan Thomas，不指定是否有关典故、文化，请批评指正。译注）进行调用的详细代码：

try{
int age = 39;

String poetName = "dylan thomas";

CallableStatement proc = connection.prepareCall("{ call set_death_age(?, ?) }");

proc.setString(1, poetName);

proc.setInt(2, age);

cs.execute();

}catch (SQLException e){ // ....}

传给prepareCall方法的字串是存储过程调用的书写规范。它指定了存储过程的名称，？代表了你需要指定的参数。
和JDBC集成是存储过程的一个很大的便利：为了从应用中调用存储过程，不需要存根（stub）类或者配置文件，除了你的DBMS的JDBC驱动程序外什么也不需要。
当这段代码执行时，数据库的存储过程就被调用。我们没有去获取结果，因为该存储过程并不返回结果。执行成功或失败将通过例外得知。失败可能意味着调用存储过程时的失败（比如提供的一个参数的类型不正确），或者一个应用程序的失败（比如抛出一个例外指示在poets数据库中并不存在“Dylan Thomas”）

结合SQL操作与存储过程

映射Java对象到SQL表中的行相当简单，但是通常需要执行几个SQL语句；可能是一个SELECT查找ID，然后一个INSERT插入指定ID的数据。在高度规格化（符合更高的范式，译注）的数据库模式中，可能需要多个表的更新，因此需要更多的语句。Java代码会很快地膨胀，每一个语句的网络开销也迅速增加。
将这些SQL语句转移到一个存储过程中将大大简化代码，仅涉及一次网络调用。所有关联的SQL操作都可以在数据库内部发生。并且，存储过程语言，例如PL/SQL，允许使用SQL语法，这比Java代码更加自然。下面是我们早期的存储过程，使用Oracle的PL/SQL语言编写：

create procedure set_death_age(poet VARCHAR2, poet_age NUMBER)

poet_id NUMBER;

begin SELECT id INTO poet_id FROM poets WHERE name = poet;

INSERT INTO deaths (mort_id, age) VALUES (poet_id, poet_age);

end set_death_age;

很独特？不。我打赌你一定期待看到一个poets表上的UPDATE。这也暗示了使用存储过程实现是多么容易的一件事情。set_death_age几乎可以肯定是一个很烂的实现。我们应该在poets表中添加一列来存储逝世年龄。Java代码中并不关心数据库模式是怎么实现的，因为它仅调用存储过程。我们以后可以改变数据库模式以提高性能，但是我们不必修改我们代码。
下面是调用上面存储过程的Java代码：

public static void setDeathAge(Poet dyingBard, int age) throws SQLException{

Connection con = null;

CallableStatement proc = null;

try {

con = connectionPool.getConnection();

proc = con.prepareCall("{ call set_death_age(?, ?) }");

proc.setString(1, dyingBard.getName());

proc.setInt(2, age);

proc.execute();

} 

finally {

try { proc.close(); }

catch (SQLException e) {}

con.close();

}

}

为了确保可维护性，建议使用像这儿这样的static方法。这也使得调用存储过程的代码集中在一个简单的模版代码中。如果你用到许多存储过程，就会发现仅需要拷贝、粘贴就可以创建新的方法。因为代码的模版化，甚至也可以通过脚本自动生产调用存储过程的代码。

Functions

存储过程可以有返回值，所以CallableStatement类有类似getResultSet这样的方法来获取返回值。当存储过程返回一个值时，你必须使用registerOutParameter方法告诉JDBC驱动器该值的SQL类型是什么。你也必须调整存储过程调用来指示该过程返回一个值。
下面接着上面的例子。这次我们查询Dylan Thomas逝世时的年龄。这次的存储过程使用PostgreSQL的pl/pgsql：

create function snuffed_it_when (VARCHAR) returns integer ''declare

poet_id NUMBER;

poet_age NUMBER;

begin

--first get the id associated with the poet.

SELECT id INTO poet_id FROM poets WHERE name = $1;

--get and return the age.

SELECT age INTO poet_age FROM deaths WHERE mort_id = poet_id;

return age;

end;'' language ''pl/pgsql'';

另外，注意pl/pgsql参数名通过Unix和DOS脚本的$n语法引用。同时，也注意嵌入的注释，这是和Java代码相比的另一个优越性。在Java中写这样的注释当然是可以的，但是看起来很凌乱，并且和SQL语句脱节，必须嵌入到Java String中。
下面是调用这个存储过程的Java代码：

connection.setAutoCommit(false);

CallableStatement proc = connection.prepareCall("{ ? = call snuffed_it_when(?) }");

proc.registerOutParameter(1, Types.INTEGER);

proc.setString(2, poetName);

cs.execute();

int age = proc.getInt(2);

如果指定了错误的返回值类型会怎样？那么，当调用存储过程时将抛出一个RuntimeException，正如你在ResultSet操作中使用了一个错误的类型所碰到的一样。

复杂的返回值

关于存储过程的知识，很多人好像就熟悉我们所讨论的这些。如果这是存储过程的全部功能，那么存储过程就不是其它远程执行机制的替换方案了。存储过程的功能比这强大得多。
当你执行一个SQL查询时，DBMS创建一个叫做cursor（游标）的数据库对象，用于在返回结果中迭代每一行。ResultSet是当前时间点的游标的一个表示。这就是为什么没有缓存或者特定数据库的支持，你只能在ResultSet中向前移动。
某些DBMS允许从存储过程中返回游标的一个引用。JDBC并不支持这个功能，但是Oracle、PostgreSQL和DB2的JDBC驱动器都支持在ResultSet上打开到游标的指针（pointer）。
设想列出所有没有活到退休年龄的诗人，下面是完成这个功能的存储过程，返回一个打开的游标，同样也使用PostgreSQL的pl/pgsql语言：

create procedure list_early_deaths () return refcursor as ''declare

toesup refcursor;

begin

open toesup for SELECT poets.name, deaths.age FROM poets, deaths -- all entries in deaths are for poets. -- but the table might become generic.

WHERE poets.id = deaths.mort_id AND deaths.age < 60;

return toesup;

end;'' language ''plpgsql'';

下面是调用该存储过程的Java方法，将结果输出到PrintWriter：
PrintWriter:

static void sendEarlyDeaths(PrintWriter out){

Connection con = null;

CallableStatement toesUp = null;

try {

con = ConnectionPool.getConnection();

// PostgreSQL needs a transaction to do this... con.

setAutoCommit(false); // Setup the call.

CallableStatement toesUp = connection.prepareCall("{ ? = call list_early_deaths () }");

toesUp.registerOutParameter(1, Types.OTHER);

toesUp.execute();

ResultSet rs = (ResultSet) toesUp.getObject(1);

while (rs.next()) {

String name = rs.getString(1);

int age = rs.getInt(2);

out.println(name + " was " + age + " years old.");

}

rs.close();

}

catch (SQLException e) { // We should protect these calls. toesUp.close(); con.close();

}

}

因为JDBC并不直接支持从存储过程中返回游标，我们使用Types.OTHER来指示存储过程的返回类型，然后调用getObject()方法并对返回值进行强制类型转换。
这个调用存储过程的Java方法是mapping的一个好例子。Mapping是对一个集上的操作进行抽象的方法。不是在这个过程上返回一个集，我们可以把操作传送进去执行。本例中，操作就是把ResultSet打印到一个输出流。这是一个值得举例的很常用的例子，下面是调用同一个存储过程的另外一个方法实现：

public class ProcessPoetDeaths{

public abstract void sendDeath(String name, int age);

}

static void mapEarlyDeaths(ProcessPoetDeaths mapper){

Connection con = null;

CallableStatement toesUp = null;

try {

con = ConnectionPool.getConnection();

con.setAutoCommit(false);

CallableStatement toesUp = connection.prepareCall("{ ? = call list_early_deaths () }");

toesUp.registerOutParameter(1, Types.OTHER);

toesUp.execute();

ResultSet rs = (ResultSet) toesUp.getObject(1);

while (rs.next()) {

String name = rs.getString(1);

int age = rs.getInt(2);

mapper.sendDeath(name, age);

}

rs.close();

} catch (SQLException e) { // We should protect these calls. toesUp.close();

con.close();

}

}

这允许在ResultSet数据上执行任意的处理，而不需要改变或者复制获取ResultSet的方法：

static void sendEarlyDeaths(final PrintWriter out){

ProcessPoetDeaths myMapper = new ProcessPoetDeaths() {

public void sendDeath(String name, int age) {

out.println(name + " was " + age + " years old.");

}

};

mapEarlyDeaths(myMapper);

}

这个方法使用ProcessPoetDeaths的一个匿名实例调用mapEarlyDeaths。该实例拥有sendDeath方法的一个实现，和我们上面的例子一样的方式把结果写入到输出流。当然，这个技巧并不是存储过程特有的，但是和存储过程中返回的ResultSet结合使用，是一个非常强大的工具。

结论

存储过程可以帮助你在代码中分离逻辑，这基本上总是有益的。这个分离的好处有：
&#8226; 快速创建应用，使用和应用一起改变和改善的数据库模式。
&#8226; 数据库模式可以在以后改变而不影响Java对象，当我们完成应用后，可以重新设计更好的模式。
&#8226; 存储过程通过更好的SQL嵌入使得复杂的SQL更容易理解。
&#8226; 编写存储过程比在Java中编写嵌入的SQL拥有更好的工具－－大部分编辑器都提供语法高亮！
&#8226; 存储过程可以在任何SQL命令行中测试，这使得调试更加容易。

并不是所有的数据库都支持存储过程，但是存在许多很棒的实现，包括免费/开源的和非免费的，所以移植并不是一个问题。Oracle、PostgreSQL和DB2都有类似的存储过程语言，并且有在线的社区很好地支持。
存储过程工具很多，有像TOAD或TORA这样的编辑器、调试器和IDE，提供了编写、维护PL/SQL或pl/pgsql的强大的环境。
存储过程确实增加了你的代码的开销，但是它们和大多数的应用服务器相比，开销小得多。如果你的代码复杂到需要使用DBMS，我建议整个采用存储过程的方式。

posted @ 2006-10-11 14:37 康文 阅读(189) | 评论 (0) | 编辑 收藏

披着盛装的稻草人-- 编程中的随笔

1 不是使用了spring ，hibernate 等企业级产品的框架，我们就是企业级产品了。不是我们采用了新瓶装旧酒的web 2.0 我们就走在技术的前沿了。我门所需要的是一个高性能的，健壮的 产品，是一个可以降低我们实施成本，一个可以树立我们企业品牌的产品。在这里我不得不对我们产品的所谓的架构们产品疑问，Archetectures,what are you doing？

2 在实现框架代码的时候，当你对采用那种实现方式犹豫不决的时，换个角度，想一想如果你是程序员，喜欢怎么这些框架。在实现框架的时候一定要考虑程序员是否能够理解你写框架的思路，除非万不得已不要用一些自以为很高明很巧妙，然而却很晦涩难懂的方法，那样的框架，程序员至少合格的程序员是不愿意使用的。我想程序员和编码工人最大的区别就是程序员不仅要知其然，还要知其所以然。

3 只有在不断实践中，才能激发你不断的求知欲。只有把学到的知识不断的应用道实践中，你才能在学习中得到满足。不要为了学习而学习（学院派，不好听点就是纸上谈兵），而是要从实际问题出发，在解决问题的过程中不断深入，不断总结，所以说，当你离开了编程的第一线，你将失去学习编程知识的欲望。当然如果你愿意，在别的领域还有更广阔的天空，但是请不要总是说自己原来编程怎么怎么，其实你已经被三振出局了。

4 想外行一样思考，想专家一样实践，一本书的名字，虽然书没有看过，但她的名子就已经非常有意思了。这岂不就是我们作需求，和作架构时的座右铭吗？既能象“外行”一样的站在客户的角度思考问题，又能象“专家”一样参与到整个产品的开发和实施当中，在实践中不断提高自我。然而，不幸的是许许多多的所谓的架构师，系统分析员们却正向着相反的方向迈进。“真正”的做到了，象“专家”一样思考，象“外行”一样实践，可悲呀可悲。
5设计做到什么样才叫做到位呢。我想只有真正的开发者才有权利发言。只有有它们才是设计的真正使用者和受害者。因为就我所知和所见，绝大多数设计都是设计者自己的游戏（当然，我可能是井底之蛙了没有见过什么好的设计），程序员所开发往往还是对着原形自己再进行一遍设计，且不说额外增加了多少工作量，浪费了多少时间，就工作质量而言，也是差强人意。毕竟大多数情况下，设计者或称为架构师的在技术方面的经验都更为丰富，对业务的理解也更为深入，另外由一个人进行设计在功能复用，和整体性能方面的考虑也更完整一些。但怎么做才能熊掌和鱼兼得呢？下面我发表一下我个人的看法：
  1 代码就是最好的设计，这句话不是我说的，是 xp开发届 中的一位大牛说的。之所以在这里引用别人的观点，并不是自己是一个xp 的fans，也并不时完全赞同xp 的理论，我只是觉得这句话得太对了，对程序员来说什么设计比代码读起来更亲切呢？。其实设计无非是向开发所着传达设计者的思想，告诉开发者系统需要开什么个对象，具有什么属性和行为，它们之间的调用关系又如何。我们在设计文档中经常使用的方法就是有class 图，协作图，和顺序图对上面所提到的进行描述。然而结果呢，面对这大量的令人畏惧的抽象图表，开发者可选择的也只有是“重整江河待后生了”。想想，这样的设计和代码能够同步吗，这样的设计文档还有什么用呢？所以说与其是这样还不如把设计变成代码，如对象属性可以这直接在代码中体现，方法可以只定义接口，实现方式可以作为代码的注释，向写需求分析用例似的来一步一步说明程序是需要怎样调用。当客户要求设文档的时候，只需要提出javadoc就可以了，而其保证和代码同步。而开发者呢，在开发前需要阅读用例，了解需求，然后在设计者已经搭好的代码框架中进行开发就可以了。如果需要修改的话，不用在去设计文档中更改，只需要修改一下代码注释就可以了，（程序员是比较懒的，不怎么愿意写写文档的）。当然了，让懒惰的程序员能够自觉地写好文档也不是一件容易事，下面也许能给你提供一个好的方法
  2 交差开发能够帮助完成最好的设计文档。
  3 设计者在开发阶段还作什么呢？                 
待续                                                               

posted @ 2006-10-11 14:36 康文 阅读(233) | 评论 (0) | 编辑 收藏

access controll

1Privilgeges
 1) Database security:
  --System security
  --Data security
 2)System privileges:Caining access to the database
 3)Object privileges:manipulationg thee content of the database objects
 4)Schemas:Collections of objects ,such as tables,views,and sequences
2System Privileges
  . More than 100 privileges are available;
  . The database administrator has high-levle system privileges for tasks such as:
    creating new user,removing user,removing tables,backing up tables
3 Creating user
 the dba creates users by using the create user statement
 create user user
 identified by password;
 e.g create user object scott
     identified by tiger;

 SQL> create user testuser
  2  identified by test;

User created

SQL> conn testuser/test@orcl2000
Not logged on

SQL> grant access session to testuser;

grant access session to testuser

Not logged on

SQL> conn digit_cc/digit_cc@orcl2000
Connected to Oracle9i Enterprise Edition Release 9.2.0.1.0
Connected as digit_cc

SQL> grant create session to testuser;

Grant succeeded

SQL> conn testuser/test@orcl2000;
Connected to Oracle9i Enterprise Edition Release 9.2.0.1.0
Connected as testuser
4 user System privileges
 once a user is created,the dba can grant specific system privileges to a user
 grant privilege[,privilege...]
 to user [,user|role,public...];

 DBA can grant a user specific system privileges
 grant create session,create table,create sequence,create view  to scott;
5 creating and granting privileges to role
' Create a role
  create role manager;
 .grant privileges to a role
  grant create table,create view to manager
 .Grant a role to user
  grant manager to kochar;
 
SQL> create role testrole;

Role created

SQL> grant create table,create view,create sequence to testrole;

Grant succeeded

SQL> grant testrole to testuser;
6 change your password
 you can change your password by using the alter user statement;
 alter user scott
 indetified by lion;
7 object privileges
 object privileges vary from object to object
 an owner has all the privilege to the object
 an owner can give specific privilege on that owner object
  grant select on auther to testuser;
  grant select on outher to testuser with grant option -- testuser also can grant it to

other user;
  grant update(department_name,location_id)
  on departments
  to scott,manager;
8 how to revoke object privileges
 --you use the revoke statement to revoke privileges granted to other users
 --privileges granted to other users through the with grant option clause are also revoked.
  revoke privilege {[,privilege...]|all} on object
  from {user[,user....]|role|public}
  [cascade constraints]
  revoke select on author from user;
9 Database Links
 Database link allow user to access data in the remote database;
SQL> create database link kjw1
  2  connect to digit_cc identified by digit_cc
  3  using 'orcl2000';

Database link created

SQL> select * from digit_cc.table_action@kjw1;

posted @ 2006-09-29 15:40 康文 阅读(233) | 评论 (0) | 编辑 收藏

database link 使用 转载

链接到远程数据库

在一个分布式的环境里，数据库链接是定义到其它数据库的路径的一个重要方法，使得远程处理天衣无缝。

要获得数据库链接的更深奥的知识，查看Oracle8i SQL Reference（Oracle8i SQL参考）和Oracle8i Concepts （Oracle8i概念手册）。详细资料的另一个极好的来源是Oracle8i Distributed Database Systems（Oracle8i分布式数据库系统手册）。

今天许多运行Oracle的机构有不止一个Oracle数据库。有时不管原计划是否这样，一个数据库中的数据可能与另一数据库中的数据关联。出现这种情况时，你可以链接这两个数据库使得用户或应用程序可以访问所有数据，就好象它们在一个数据库中。当你这么做时，你就有了一个分布式数据库系统。

如何将两个数据库链接在一起呢？使用一个数据库链接来完成。数据库链接是定义一个数据库到另一个数据库的路径的对象。数据库链接允许你查询远程表及执行远程程序。在任何分布式环境里，数据库链接都是必要的。

简单案例

数据库链接的目的是定义一条到远程数据库的路径，使你可以通过在本地执行一条SQL语句来使用那个数据库中的表和其它的对象。例如，你在一个远程数据库上有一个称之为"geographic feature name"的表，而你想在已连接到你本地数据库的情况下访问那些数据。数据库链接正是你所需要的。在建立它之前，你必须搜集如下信息：

一个网络服务名称，你的本地数据库事例能够使用它来与远程事例相连接远程数据库上的有效用户名和口令网络服务名称是每一个数据库链接必需的。每一次你从客户机PC使用SQL*Plus连接到你的数据库时都要使用服务名称。在那些情况下，你提供给SQL*Plus的网络服务名称是通过在你的客户机上的nsnames.ora文件中查找它们来解析的。在数据库链接中使用的网络服务名称也是如此，除非是那些名字是使用驻留在服务器上的tnsnames.ora文件来解析。

在你定义数据库链接时指定的用户名和口令，用于建立与远程事例的连接。不需硬编码用户名和口令，建立数据库链接也是可能的甚至是值得选取的。既然这样，现在我们注意这个最直接的例子。

下列语句建立了一个数据库链接，它允许访问客户帐户，这个帐户是事先在GNIS数据库建好的：

CREATE DATABASE LINK GNIS
CONNECT TO GUEST IDENTIFIED BY WELCOME
USING 'GNIS';

链接名称GNIS紧随LINK关键字。当连接到远程事例时，CONNECT TO...IDENTIFIED子句指定UEST/WELCOME作为用户名和口令使用 。USING子句指定通过网络服务名称GNIS建立连接。使用这一链接，现在你可以在远程数据库上查询数据。例如：

SQL> SELECT GFN_FEATURE_NAME
2 FROM GNIS.FEATURE_NAMES@GNIS
3 WHERE GFN_FEATURE_TYPE='falls'
4 AND GFN_STATE_ABBR='MI'
5 AND GFN_COUNTY_NAME='Alger';

GFN_FEATURE_NAME
_________________
Alger Falls
Au Train Falls
Chapel Falls
Miners Falls
Mosquito Falls
Tannery Falls
..

在SELECT语句中@GNIS紧随表名称，说明GNIS.FEATURE_NAMES表是在远程数据库，应该通过GNIS链接访问，链接类型Oracle支持几种不同类型的链接。这些类型相互重叠，有时难以通过选项进行分类。当你建立数据库链接时，你需要从下面选取：

Public（公用）或Private （私有）链接

权限类: Fixed User（固定用户）, Connected User（连接用户）或 Current User（当前用户）
Shared Link（共享链接）或 Not Shared Link（非共享链接）
每次创建数据库链接时，你要自觉不自觉地做这三种选择。

公用链接与私有链接相对比

公用数据库链接对所有的数据库用户开放访问权。前面显示的是私有数据库链接，它只对建立它的用户授权。公用数据库链接更为有用，因为它使你不必为每一个潜在用户创建单独的链接。为了建立一个公用数据库链接，使用如下显示的PUBLIC关键字：

CREATE PUBLIC DATABASE LINK GNIS
CONNECT TO GUEST IDENTIFIED BY WELCOME
USING 'GNIS';

即使这是一个公用链接，用户名仍旧固定。所有使用这个链接的用户都作为用户GUEST连接到远程数据库。

使用数据库链接访问远程表

图1 数据库链接GNIS，指明网络服务名称，链接PROD事例到GNIS事例中的FEATURE_NAMES表。

权限类

当你建立一个数据库链接时，关于你如何授权对远程数据库进行访问，有三种选择。这三种选择代表了数据库链接的另一种分类方法。这三种类别如下：

固定用户。为远程数据库链接指定用户名和口令，作为数据库链接定义的一部分。
连接用户。在不指定用户名和口令时创建的数据库链接。
当前用户。建立数据库链接并指定CURRENT_USER关键字。
固定用户数据库链接是指在创建链接时为远程数据库指定用户名和口令。这一链接不管什么时候使用，也无论谁使用，都使用相同的用户名和口令登陆到远程数据库。到目前为止你在本文中所看到的都是固定用户链接。

固定用户链接，尤其是公用固定用户链接的一个潜在问提是他们把远程系统上的同一帐户给了许多本地用户。从安全角度来说，如果所有的本地用户在远程系统上拥有同一个帐户，责任就要折中，这取决于用户的数量 。如果数据丢失，几乎不可能确定破坏是如何发生的。另一个潜在问题是公用固定用户链接将对远程数据库的访问权给了所有的本地数据库用户。

如果你不想在数据库链接中嵌入用户名和口令，Oracle提供给你另一个非常有用的选择。你可以建立一个连接用户链接。连接用户链接是这样的链接，它通过任一个正在使用该链接的本地数据库的用户的用户名和口令登陆到远程数据库。你可以通过简单地空出用户名和口令来建立一个连接用户链接。考虑如下定义：

CREATE PUBLIC DATABASE LINK GNIS

USING 'GNIS';

链接名是GNIS。它连接到远程数据库连接时使用的网络服务名称是GNIS，但是没有指定用户名和口令。当你在查询中使用这个链接时，它将向远程数据库发送你当前的用户名和口令。例如，如果你使用AHMAD/SECRET 登陆到你的本地数据库，那么AHMAD/SECRET将是你登陆到远程数据库时使用的用户名和口令。

为了使用一个连接用户链接，你必须在远程数据库上有一个帐号，了解这一点是很重要的。不但这样，而且你在两个数据库上应使用同样的用户和口令。如果本地登陆使用AHMAD/SECRET，那么登陆到远程数据库时也必须使用同样的用户名和口令。使用连接用户链接时，如果你的口令不同，你就无权登陆。

公用连接用户数据库链接尤其有用，因为你可以建立一个可被所有用户访问的链接，并且所有用户被分别使用他或她自己的用户名和口令授权。你获得责任方面的利益，没有将远程数据库向你的本地数据库上的每一位用户开放。代价是你必须在两个数据库上建立用户帐户，并且你必需确信口令保持一致。

当前用户链接通过使用CURRENT_USER关键字建立并且与连接用户链接相似。只有当使用Oracle Advanced Security Option（Oracle高级安全选项）时，你才能使用当前用户链接，这个链接只对授权使用X.509认证的用户有用。

共享链接

共享数据库链接是指该链接的多个用户可以共享同一个底层网络连接。例如，在有四位用户的MTS（多线程服务器）环境下，每一个共享服务器进程都将与远程服务器有一个物理链接，这四位用户共享这两个链接。
表面上，共享链接乍一听起来像是一件好事。在某些环境下的确如此，但是，当你考虑使用共享链接时，应当意识到这有许多局限性和警告：

如果你使用一个专用的服务器连接来连接到你的本地数据库，链接只能在你从那些连接中创建的多重会话间共享。 在MTS环境里，每一个共享服务器进程潜在地打开一个链接。所有的会话被同一共享服务器进程提供并且分享被那个进程打开的任意共享链接。因为在MTS环境里的一个共享服务器进程能够服务于许多用户连接，共享链接的使用可能导致打开的链接远多于所必须的链接。用SHARED关键字建立共享数据库链接。还必须使用AUTHENTICATED BY 子句在远程系统上指定一有效的用户名和口令。如下命令建立一个共享的、公用的、连接用户数据库链接：

CREATE SHARED PUBLIC DATABASE LINK GNIS
AUTHENTICATED BY DUMMY_USER IDENTIFIED BY SECRET
USING 'GNIS';

要获得创建链接和管理分布式系统的更多资料，请查阅Oracle Technology Network (http://otn.oracle.com/)。
使用AUTHENTICATED BY子句稍微有些困扰，但是由于实现共享链接的方式安全性决定它是必须的。这个例子中的用户名和口令DUMMY_USER/SECRET必须在远程系统上有效。然而，远程系统上使用的帐户仍就是连接用户的帐户。如果我以JEFF/SECRET登陆到我的本地数据库并使用我刚建好的共享链接，将会发生以下一系列事件：

为了打开链接，Oracle使用DUMMY_USER/SECRET向远程数据库授权。 然后，Oracle试图使用HMAD/SECRET使我登陆到远程数据库。共享链接的主要目的是减少两个数据库服务器之间的底层网络连接数量。它们最适合于MTS环境，在那你拥有大量的通过这一链接访问远程数据库的用户。观念上，你想让用户数量超过共享服务器进程的数量。那么你可以通过为每一共享服务器进程打开一个链接而不是每位用户打开一个链接的方法，节省资源。

查找关于数据库链接的资料

你可以从几个数据字典视图中获得建立好的数据库链接的资料。DBA_DB_LINKS视图为每一定义的链接返回一行。OWNER 列和DB_LINK列分别显示了这一链接的所有者及名称。对公用数据库链接，OWNER列将包含'PUBLIC'。如果你建立固定用户链接，用户名应在DBA_DB_LINKS视图的USERNAME列里，但是口令只能从SYS.LINK$视图中看到。默认情况下，只有具有SELECT ANY TABLE系统权限的DBA能够访问SYS.LINK$视图查看口令。你应该保护访问那个视图的权限。ALL_DB_LINKS 视图和 USER_DB_LINKS视图与 DBA_DB_LINKS视图相类似-它们分别显示了你能够访问的所有链接及你所拥有的全部链接。最后，V$DBLINK动态性能视图向你显示出任意给定时间你-当前用户，打开的全部数据库链接。

全局性的数据库名称

在分布式环境里，Oracle建议你的数据库链接名应与它们连接到的数据库的全局性名称相匹配。因此如果你正在连接到名称为GNIS.GENNICK.ORG的数据库，你应当将你的数据库链接命名为GNIS.GENNICK.ORG
为确定数据库的全局性名称，以SYSTEM登陆并查询GLOBAL_NAME视图：

SQL> SELECT * FROM GLOBAL_NAME;

GLOBAL_NAME
_______________
GNIS.GENNICK.ORG

由于历史的原因，默认情况下，全局性名称与数据库链接名称的之间的链接不是强制性的。不过，你可以通过设置GLOBAL_NAMES的初始化参数为TRUE来改变这一行为。例如：

SQL> SHOW PARAMETER GLOBAL_NAMES

NAME TYPE VALUE
________________________________________________________
global_names boolean TRUE

用于产生这个范例的事例要求你使用的数据库链接名，必须与目标数据库的全局性数据库名称相匹配。注意与一些Oracle文档中说的相反，关键是你的本地事例的GLOBAL_NAMES设置。如果你的本地事例中GLOBAL_NAMES=FALSE，你就能够使用数据库链接，而不用管它们是否与远程数据库的全局性名称相匹配。总的来说，如果你设置GLOBAL_NAMES=TRUE，你应该在你的所有事例中一律这么做。

posted @ 2006-09-29 15:35 康文 阅读(2141) | 评论 (0) | 编辑 收藏

some database object

1 sequence
  1)   automatically generatess unique numbers
   is a sharable object
   is typically used to create a primary key value
   replaces applicaition code
   speeds up the efficiency of accessing sequence
   create sequence sequence
   [increment by n]
   [start with n]
   [{maxvalue n |nomaxvalue}]
   [{minvalue n |nominvalue}]
   [{cycle|nocycle}]
   [{cache n |nocache}]

   create sequence dept_deptin_seq
   increment by 10
   start with 120
   maxvalue 9999
   nocache
   nocycle
  2) Confirming Sequences
   verify your sequence values in the user_sequences data dictionary table
   select sequence_name,min_value,max_value,increment_by,last_number
   from user_sequences;
   the last_number display the next available sequence number if nocache is specified
  3)nextval and currval Pseudocolumns
    --nextval return thee next available sequence value,it return a unique value every time
it si referenced,even for different ueer;
    --currval obtains the current sequence value;
    --nextval must be issued for that sequence before curval contains a value;
  4) Using a Sequence
    -- Caching sequence values in the memory give faster access to these values;
    -- Gaps in sequence value can occur when
       a rollback occurs
       b the system crashes
       c A sequence us used in another table;
   5) alter sequence test increment by 10;
      you can change all properties of the sequence except the start with .
   6) remove sequence
      drop sequence test;
2 index
  1) how are indexes created
   Automatically : a unique index is created automatically when you create primary key or

unique constraint in a table definition,
   Manually: user can create nounique index on column to speed up access to the rows.
   create index testindex on autoer(lanme);
  2) When to Create an index
   ypu should create an index if:
   . a column contains a wide range of values
   . a column contains a large number of null values
   . one or more columns are frequently used together in where clause or a join condition;
   . The table is large and most queries are expected to retrieve less than 2 to 4 percent

of the rows;
   3) When not to create an index
   this usually not worth creating an index if:
   . the table is small
   . The columns are not often used as a condition in the query.
   . Most queries are expected to retrieve more than 2 to 4 percent of the rows in the

table
   . the indexed columns are referenced as part of an expression.
   4)Confirming indexes
    . The user_indexes data dictionary view contains the name of the index and tis uniquess
    . the user_ind_columns view contains the index name,the table name,and the column name.
    select ic.index_name,ic_column_name,ic.column_position,ic_col_pos,ix.uniqueness
    from user_indexed ix,user_ind_columns ic
    where ic.index_name=ix.index_name
    and ic.table_name='employees';
  5)基于函数的索引
  . a function-based index is an index based on expressions
  . The index expression is built form table columns,constraints,SQL functions and user-

defined functions
   create index testindex2
   on autors (upper(au_fname));
  
   select * from authors
   where upper(au_fname) like 'B%';
  6) remoe index
   drop index index_name;
3 synonyms
  Simplify access to objects by creating a synonym
   . Ease referring to a table ownerd by anther user
   . Shorten lengthy object names;
   create [publi] synonym synonym for object;

posted @ 2006-09-29 11:31 康文 阅读(185) | 评论 (0) | 编辑 收藏

使用游标

posted @ 2006-09-28 15:32 康文 阅读(150) | 评论 (0) | 编辑 收藏

createing view

1Why Use Views
  to restrict data access
  to make complex query easy
  to provide data independence
  to provide defferent view of the same data
2 Creating a View
  1)create [or replace] [force|noforce] view view
  as subquery
  force : create view wether the referenced object existed or not
 
  desc view_name;
 2)create a view by using column aliases in the subquery
  create view salv50
  as select employee_idIO_NUMBER,last_name NAME,slaary*12 ANN_SALARY
  from employees
  where department_id=50;
3 Modigy a View
  1) Modigy the emplvu80 view by using create or replace view clause.Add an alias for each

column name;
   create or replace view empvu80
   (id_number,name,sal,department_id)
   as select employee_id,first_name||" "||last_name,salary.department_id
   from employees
   where department_id=80;
   column aliases in the create view clause are listed in the same order as the columns in

the subquery
   note : alter view_name is not a valid command.
4 Create a Complex View
  Create a complex view that contains group functions to display values from two tables
  create view dept_sum_vu
   (name,minsal,maxsal,avgsal)
  as
   select d.department_name,min(e.salary),max(e.salary),avg(e.salary)
   from employees e,departments d
   where e.department_id=d.department_id
   group by d.department_name;
5 Rules for performs DML operaton on a view
  1) You can perform DML operation on simple views
  2) You can not romove a row if the view contains the following:
    --group functions
    --a group by clause
    --the distince keyword
    -- rownum keyword
    -- column defined by expressions
6 Using the with check option Clause
  1) you can ensure that dml operatons performed on the view stay within the domain of the

view by using the with check option clause.
  creaate view test1
  as
  select * from emp where qty>10;
  with check option;
  update testview1 set qty=10
  where ster_id=6830;
  --when you doing the following update operation
  update testview1 set qty=5 where id=10;
  -- an error will report
  --you violate the where clause
  2)Any attempt to change the department number for any row in the view fails because it

violates the with check option constraint
   create or replace view empvu20
   as
   select * where department_id=20
   with check option constriant empvu20_ck;
7 Denying DML Operations
  1 You can ensure that no dml operations occur by adding the with read only option to your

view definition.
  2)Any attempt to a DML on any row in the view resuls in an oralce server error.
8 remove veiw
  drop view_name
9 inline view
  1) an inline view is a subquery with an alias that you can use within a sql statement.
  2) a named subquery in the from clause of the main query is an exqmple of an inline view
  3) an inline view is not a schema object.
10 Top-N Analysis
 1)Top_N querise ask for the n largest or smallest values of a column.
 2)Both largest values and smallest values sets considered Top-N queries
  select * from (select ster_id,qty from sales);
 example
  To display the top three earner names and salaries from the employees
  select rownum as rank,last_name,salary
  from (select last_anme,slary from employee
        order by slary desc)
  where rownum<=3;
 

posted @ 2006-09-27 18:30 康文 阅读(265) | 评论 (0) | 编辑 收藏

使用复合变量.

1 pl/sql 集合 处理单列多行数据库，使用的类型为标量类型
 1） 索引表
  type ename_table_type is table of emp.ename%type
    index by binary_integer;
  ename_table ename_table_type;
  begin
    select ename into ename_table(-1) from emp
      where empno=&no;
    dbms_output.put_line('雇员名：'||ename_table(-1));
  end;
 
   set serveroutput no
   declare
     type area_table_type is table of number
        index by varchar2(10);
     rea_table area_table_type;
    begin
        area_table('beijing'):=1;
        area_table('shanghai'):=2;
        area_table('guangzhou'):=3;
        dbms_output.put_line(area_table.first);
        dbms_output.put_line(area_table.last);
    end;
     2) 嵌套表
      索引表类型不能作为累得数据类型使用，但是嵌套表可以作为表类的数据类型使用。
当使用嵌套表元素时，必须先用其构造方法初始化其嵌套表：
       a  在pl/sql 块中使用嵌套表
        declare
          type ename_table_type is table of emp.ename%type;
          ename_table ename_table_type;
        begin
           ename_table:=eanme_table_type('2','2','3');
           select ename into ename table(2) from emp where empno=&no;
           dbms_ouput.put_line(ename_table(2));
        end;
      b 在表中使用嵌套表
        create type phone_type is table of varchar2(20);
        create table employee(
          id number (4),name varchar2(10),sal number(6,2),
          phone phone_type
        )nested table phone store as phone_table;
       -- 为嵌套表插入数据
        insert into employee values(2,'scott',200,phone_type('2222','333333'));
       －－检索嵌套表累得数据
        set erveroutput on
        declare
          phone_table phone_type;
        begin
          select phone into phone_table
          from employee where id=1;
          for i in 1..phone_table.count loop
            dbms_output.put_line(phone_table(i));
          end loop;
        end;
       -- 更新嵌套表列的数据
         delcare
            phone_table phone_type:=('44444','555555');
         begin
            update employee set phone=phone_table
            where id=1;
         end;
    3) 变长数组
      在使用varray 时必须指定最大个数，和数据类型,在使用其元素时必须进行初始化
      type ename_table_type is varray(20) of emp.ename%type;
      ename_table ename_table_type:=ename_table_type('1','2');
     
      -- 在快中使用varray
      declare
         type ename_table_type is varray(20) of emp.ename％type；
         ename_table ename_table_type:=ename_table_type('mary');
         begin
            select ename into ename_table(1) form emp
               where empno=$no;
          end;
      --在表列中使用varray
       create type phone type is varray(20) of varchar2(20);
       create table employee(
         id number(4),name varchar2(10),
         sal number(6,2),phone phone_type);
      
     3)记录表
      记录表结合了记录和集合的优点
        declare
          type emp_table_type is table of emp%rowtype
          index by binary_integer;
        emp_table emp_table_type;
        begin
          select * from into emp_table(1) from emp
          where empno=&no;
          dbms_output.put_line(emp_table(1).ename);
        end;
      4)多维集合
       1 多级varray
       declare
        --define 一维集合
          type al_array_type is varray(10) of int;
        --定义二维集合
          type nal_varray_type is varray(10) of a1_varray_type;
        --初始化二维集合
          nvl nal_varray_type:=nal_varray_type(
            a1_varray_type(1,2),
            a1_varray_type(2,3)
          )
         beign
           for i in 1..nal_varray_type.count loop
              for j in 1..a1_array_type.count loop
                dbms_out.putline(nvl(i)(j));
              end loop;
           end loop;
        end;
       2 使用多级嵌套表
        table a1_table_type is table of int;
        table nvl_table_type is table of a1_table_type;
        nvl nvl_table_type:=nvl_table_type(
          a1_table_type(1,2),
          a1_table_type(2,3)
        );
2 集合方法
  1) exist
   if ename_table.exists(1) then
    ename_table(1):='scott';
   2) count 返回当前集合变量中的元素总个数
    ename_table.count
   3) limit 返回集合元素的最大个数  只有varray 有
   4)first and last
       ename_table.first
       ename_table.last
   5) prior 和next
    ename_table.prior(5); －－返回元素5的前一个
    ename_table.next(5);  --  后一个
   6) extend
    使用于varray 和 嵌套表。
    extend add a null value
    extend (n) add n null value
    extend (n,i)add n i value
    declare
      type ename_table_type is varray(20) of varchar2(20);
      ename_table ename_table_type;
    begin
      ename_table:=ename_table_type('mary');
      ename_table.extend(5,1);
      dbms_output.put_line(ename_table.count);
    end;
   7) trim
   trim remove one element from the tail of the collection.
   trim(n) remove n element from the tail of the colleciton.
   8)delete
    delete: delete all the elements
    delete(n) :delete the nth elements
    delete(m,n): delete the elements from m to n
3 集合赋值
  1)将一个集合的数据赋值给另一个集合.clear the destination collectins and set the original

collection
   delcare
    type name_varray_type is varray(4) of varchar2(10);
    name_array1 name_varray_type;
    name_array2 name_varray_type;
   begin
     name_array1:=name_varray_type('scott','smith');
     name_array2:=name_array_type('a','b','c');
     name_array1:=name_array2;  
   end;
  
 
  type name_array1_type is varray(4) of varchar2(10);
  type name_array2_type is varray(4) of varchar2(10);
  name_array1 name_array1_type;
  name_array2 name_array2_type;
  具有相同的数据类型，单具有不同的集合类型不能构赋值
  2) 给集合赋城null 值
    可以使用delete 或 trim
    也可以使用 空集合赋给目表集合
    type name_varray_type is varray(4) of varchar2(10);
    name_array name_varray_type;
    name_empty name_varray_type;
   
    name_array:=name_varray_type('1','2');
    name_array:=name_empty;
  3) 使用集合操作赋和比较集合都是10g 的内容，p176 先略过。
4 批量绑定
  执行单词sql 操作能传递所有集合元素的数据。
  1 forall 语句
  用于insert update 和delete操作。在oracle9i 中forall 语句必须具有连续的元素
    1) using forall on insert
     declare
        type id_table_type is table of number(6)
        index by binary_integer;
        type name_table_type is table of varchar2(2)
        index by binary integer;
        id_table id_table_type;
        name_table name_table_type;
      begin
         for i in 1..10 loop
           id_table(i):=i;
           name_table(i):='Name'||to_char(i);
         end loop;
         forall i in 1..id_table.count
           insert into demo demo values(id_table(i),name_table(i));
      end;
     2)using forall on using update
       forall i in 1..id_table.count
           upate demo set name:=name_table(i)
              where id:=id_table(i);
     3)using forall on using delete
        forall i in 1..id_table.count
            delete from demo where id:=id_table(i);
     4) using forall on part of the collection
        for i in1..10 loop
          id_table(i):=i;
          name_table(i):="name"||to_char(i);
        end loop;
        forall i in 8..10 l
           insert into demo values(id_table(i),name_table(i));
   2 bulk collect
     is fit for select into ,fetch into and dml clause
     1) using bulk collect
      declares  
        type emp_table_type is table of emp%rowtype
         index by binary_integer;
        emp_table emp_table_type;
      begin
         select * bulk collect into emp_table
          from emp where deptno=&no;
         for i in 1..emp_tablee.count loop
            dbms_output.put_line(emp_table(i).ename);
         end loop;
      2) 在dml 的返回字句使用bulk collect 字句
         declare
          type ename_table_type is table of emp.ename%type;
           ename_table ename_table_type;
          begin
             deletee from emp where deptno=&no
             returning ename bulk_collect into ename_table;
          for i in 1..ename_table.count loop
            dbms_output.put(ename_table(i));
          end loop;
        end;
          end;
      end;

posted @ 2006-09-27 15:46 康文 阅读(197) | 评论 (0) | 编辑 收藏

including constraint

1 What are Constrains
  1) Constrains enforce on the table level
  2) Constrains the deletion of a table if there are dependencies
2 Constrain Guidelines
  1) Name a constraint or the oracle generate a name by the sys_cn format
  2) Create a constraint either
     --At the same time as the table is created.or
     --After the table has been created
  3)Define a constraint at the column or table level
  4)view constraint in the data dictionary
3 Crete a constraint
  create table test2
  (id int not null,-- column level
   lname varchar(20),
   fname varchar(20),
   constraint uk_test2_1 unique(lname,fname))--table level
4 The not null Constraint
  create table employees(
   employee_id number(6),
   last_name   varchar2(25) not null  --system named
   hire_date   DATE
               constraint emp_hire_date not null --User named
5Foreign key
  create table test3
  (rid int,
   name varchar(30),
   constraint fk_test3_1 foreign key(rid) reference test2(id));
  froeign key constraint keywords
    foreign key :Define the column in thee child table at the table constrain level.
    references  :Identifies the table and column in the parent table.
    on delete cascade: Delete the dependent rows in the child table when a row in the    

parent table is deleted
    on delete set null:Convert the dependent foreign key values to null when a row in the
    parent table is deleted.
  
    --parent table referenced table
    --child table refernce other table
6 The check Constraint
  Define a condition that each row must be satify
  alter table test3
  add constrain ch_test3 check(name like 's%')
7 Dropping a Constraint
  1) Remove the manager constraint form the employee table
   alter table test3
   drop constriant test3_manager_fk
  2) Remove the primary key constraint on the departments table and drop the associated
   foreign key constraint on the employees.department_id column
   alter table departments
   drop primary key cascade
8 Disabling and enable Constraints
  1)Execute the disable clause of the alter table statment to deactive an integrity

constraint
  2)Apply the cascade option to disable dependent integrity constrints
  alter table employees
  disable constraint emp_emp_id_pl cascade
  3) enabling Constraints
  .Active an integrity constraint currently disabled in the table definition by using the

enable clause.
   alter table employees
   enable constraint emp_emp_id_pk;
  a unique  or a primary  index is automatically created if you enable a unique key or a

primary key constraint 
 8 View Constraints
  select constraint_name,constriant_type,serch_condition
  from user_constraints
  where table_name='employees'
 9 view the columns associated with constraints
 select constraint_name,column_name
 from user_cons_columns
 where table_name='employees'

posted @ 2006-09-26 14:44 康文 阅读(218) | 评论 (0) | 编辑 收藏

OpenSessionInViewFilter解决Web应用程序的问题 转自：Potain 的BLOG

protected void doFilterInternal(HttpServletRequest request, 
             HttpServletResponse response,
	     FilterChain filterChain) throws ServletException, IOException {
	SessionFactory sessionFactory = lookupSessionFactory();
	logger.debug("Opening Hibernate Session in OpenSessionInViewFilter");
	Session session = getSession(sessionFactory);
	TransactionSynchronizationManager.bindResource(sessionFactory, 
             new SessionHolder(session));
	try {
		filterChain.doFilter(request, response);
	}
	finally {
		TransactionSynchronizationManager.unbindResource(sessionFactory);
		logger.debug("Closing Hibernate Session in OpenSessionInViewFilter");
		closeSession(session, sessionFactory);
	}
}

publicfinal void setSessionFactory(SessionFactory sessionFactory) {
    this.hibernateTemplate = new HibernateTemplate(sessionFactory);
  }
 protectedfinal HibernateTemplate getHibernateTemplate() {
  return hibernateTemplate;
 }

publicabstract class BaseHibernateObjectDao
	extends HibernateDaoSupport
	implements BaseObjectDao {
protected BaseEntityObject getByClassId(finallong id) {
		BaseEntityObject obj =
			(BaseEntityObject) getHibernateTemplate()
				.execute(new HibernateCallback() {
publicObject doInHibernate(Session session)
				throws HibernateException {
				return session.get(getPersistentClass(), 
                                       newLong(id));
			}
		});
		return obj;
	}
public void save(BaseEntityObject entity) {
		getHibernateTemplate().saveOrUpdate(entity);
	}
public void remove(BaseEntityObject entity) {
		try {
			getHibernateTemplate().delete(entity);
		} catch (Exception e) {
			thrownew FlexEnterpriseDataAccessException(e);
		}
	}
public void refresh(final BaseEntityObject entity) {
		getHibernateTemplate().execute(new HibernateCallback() {
publicObject doInHibernate(Session session)
				throws HibernateException {
				session.refresh(entity);
				returnnull;
			}
		});
	}
public void replicate(finalObject entity) {
		getHibernateTemplate().execute(new HibernateCallback() {
publicObject doInHibernate(Session session)
				throws HibernateException {
				session.replicate(entity, 
                                ReplicationMode.OVERWRITE);
				returnnull;
			}
		});
	}

publicObject execute(HibernateCallback action) throws DataAccessException {
	Session session = (!this.allowCreate ?
		SessionFactoryUtils.getSession(getSessionFactory(), 
                  false) :
		SessionFactoryUtils.getSession(getSessionFactory(),
                  getEntityInterceptor(),
                  getJdbcExceptionTranslator()));
	boolean existingTransaction =  
          TransactionSynchronizationManager.hasResource(getSessionFactory());
	if (!existingTransaction && getFlushMode() == FLUSH_NEVER) {
		session.setFlushMode(FlushMode.NEVER);
	}
	try {
		Object result = action.doInHibernate(session);
		flushIfNecessary(session, existingTransaction);
		return result;
	}
	catch (HibernateException ex) {
		throw convertHibernateAccessException(ex);
	}
	catch (SQLException ex) {
		throw convertJdbcAccessException(ex);
	}
	catch (RuntimeException ex) {
		// callback code threw application exception
		throw ex;
	}
	finally {
		SessionFactoryUtils.closeSessionIfNecessary(
                    session, getSessionFactory());
	}
}

publicstatic void closeSessionIfNecessary(Session session, 
    SessionFactory sessionFactory)   
    throws CleanupFailureDataAccessException {
	if (session == null || 
	   TransactionSynchronizationManager.hasResource(sessionFactory)) {
		return;
	}
	logger.debug("Closing Hibernate session");
	try {
		session.close();
	}
	catch (JDBCException ex) {
		// SQLException underneath
		thrownew CleanupFailureDataAccessException(
		"Cannot close Hibernate session", ex.getSQLException());
	}
	catch (HibernateException ex) {
		thrownew CleanupFailureDataAccessException(
		"Cannot close Hibernate session", ex);
	}
}

Category parentCategory  = new Category ();
	parentCategory.setName("parent");
	dao.save(parentCategory);
	Category childCategory  = new Category();
        childCategory.setName("child");
	parentCategory.addChild(childCategory);
	dao.save(childCategory);
	Category savedParent = dao.getCategory("parent");
	Category savedChild = (Category ) savedParent.getChildren().get(0);
	assertEquals(savedChild, childCategory);

posted @ 2006-09-26 11:01 康文 阅读(547) | 评论 (0) | 编辑 收藏

creating and manipulation table

posted @ 2006-09-25 17:59 康文 阅读(196) | 评论 (0) | 编辑 收藏

Data manipulation

posted @ 2006-09-25 16:25 康文 阅读(234) | 评论 (0) | 编辑 收藏

sequence 的用法

posted @ 2006-09-24 16:08 康文 阅读(709) | 评论 (0) | 编辑 收藏

subqueries

1 Guidelines for Using Subqueries
 a Enclose subqueries in parenttheses
 b placce subqueries on the right side of the comparision condition
 c the order by clause in the subquery is not needed
 d using single-row operators with single-row subqueries and use multiple -row operator with multiple-row subqueries .
  single-row subqueries can work as a expression,and muitiple-row subqueries can only be used with in all any ,i will talk it later
  select last_name where job_idd=(select job_id
                                  from employees
                                  where imployee_id=141)
2 The HAVING CLause with Subqueries
 a The Oracle server execute subqueries first
 b The Oracle return result into the HAVING clause of the main query
  select department_id,min(salary)
  from employee
  group by department_id
  having min(salary)>
                     (select min(salary)
                      from employees
                      where department_id=50);
3 Multiple-Row Subqueries
  a Return  more than one row
  Using mutiple-row comparsion operator
  select employee_id
  from employees
  where salary<any
                  (select salary
                   from employees
                   where job_id='ddd')

  select employee_id
  from employees
  where salary<all
                  (select salary
                   from employees
                   where job_id='ddd')
   select emp.last_name
   from employees emp
   where emp.employee_id not in
                               (select mgr.manager_id
                                from employees mgr)

posted @ 2006-09-22 16:25 康文 阅读(250) | 评论 (0) | 编辑 收藏

jointable

posted @ 2006-09-22 14:55 康文 阅读(358) | 评论 (0) | 编辑 收藏

sql function

1 "'
2 ||
3 isql*plus  http://127.0.00.1/isqlplus
4 desc author
5 initcap('SQL Course')
  INSERT('JellwWord','W')  6
   LPAD (salary,10,'*')  *****24000
   RPAD (salary,10,'*')  24000*****
   TRIM ('H' from 'HolloWorld') olloWord
   substr('helloword',1,5)  hello
   substr('helloword',-1,5) oword
6  Number Functions
   round(45.926,2)   45.93
   round(45.926,-2) 0
   round(55.926,-2) 100
   trunc(45.926,2)   45.92
   mod(1600,300)  100
7 data function
   systdate
   (sysdate-hire_date)/7 as weeks
   months_between  number of months between two dates
   months_between ('01-sep-95','11,jan-94')  19.6774194
   add_months      add calendar months to date
   add_months('11-JAN-94',6)  '11-JUL-94'
   next_day        next day of the date specified
   next_day('01-SEP-95','FRIDAY') '08-SEP-95'
   last_day        last day of the month
   last_day('01-feb-95')  '28-feb-95'
   round           round date
   assume sysdate='25-jul-95'
   round(sysdate,'month') 01-aug-95
   round(sysdate,'year')  01-JAN-96
   trunc           truncate date
   trunc(sysdate,'month') 01-Jul-95
   trunc(sysdate,'month') 01-JAN-95
8  Conversion Functions 
  1) implicit data typ conversion
   varchar2 or char  ---number
   varchar2 or char  ---date
   numbeer           ---varchar2
   date              ---varchar2
  2) to_char(date,'format')
  format:
    YYYY Full year in numbers
    YEAR Year spelled out
    MM   Two-digit value for month
    MONTH Full name of the month
    MON  THree-letter abbreviation of the month
    DY   Three-letter abbreviation of the day of the week
    DAY  Full name of the day of hte week
    DD   Numberic day of the month
    HH24:MI:SS AM  15:45:32:PM
    DD "of"  MONTH 12 of october
  3) to_char function with number 
   TO_CAHR(number,'format_model')
   These are some of the format elements you can use with the to_char function to display number as a character.
    9 Reqresents a number
    0 Forces a zero to be displayed
    $ Places a flationg dollar sign
    L Uses the floating local currency symbol
    . Prints a decimal point
    , Print a thousand director
  select to_char(qtym,"$999.99")
  4) Using t_number and to _date functions
   a converting a character string to a number format using to_number function
   to_number(char,"format")l
   b converting a character string to a date format
   to_date(char,"format")
5 Nesting Functions
.Single-row function can be nested to many level
.Nested function can be evaluated from deepest level
6General Function
These function work with any data type and pertain to using nulls
nvl(expr1,expr2);
nvl2(expr1,expr2,expr3)
nullif(expr1,expr2)
coalesce(expr1,expr2,,,,exprn)
 1) nvl function
 convert a null to an actual function
 a Data type can be used are data character and number
 b Data types must match                              
 (set wrap off
  set line 1000
 )
 2)Using the COALESCE Function
 a The advantage of the coalesce function over nal function is that coalesce function can take multiple alternative value
 b If the first value is not null, it return that expression,otherwise,it does a coalesce of remaining expressions
6 Conditional Expressions
 a Provide the use of if-then-else logic
 b use two methods: case expression decode function
  select last_name,job_id,salary,
         case job_id when 'it' then 1*salary
                      when 'manager' then 1.2*salary
         else salary end;
  from employee.

  select last_namek,job_id,salary,
         decode(job_id,'it' ,1*salary,
                        'manager',1.2*salary,
                salary)
   from employees
  

posted @ 2006-09-22 11:50 康文 阅读(360) | 评论 (0) | 编辑 收藏

Aggregating Datas Using Group Functionbs.

1 What Are Group Functions
Group functions operatee on sets of rows to give one result per group
 1)agg,count,max,min,stddev,sum,variance
 select avg(salary),max(salary),min(salary),sum(salary)
 from employees
 where job_id like '%REP%'

 select count(*) from
 select count(address) from authors
 count the valid count of the address (exclude the null value)
 2) Using theDISTINCT Keyword
  count(distinct expr) return thee number of the distinct non-null value of the expr
  select count(distincee department_id) from employees
 3)Group functions and null values
  group functions ignore null values in the clumn
 4) Using thee NVL Function with Group Functions
  The nul function force group funtion to include null values
  select avg(nvl(commission_pct,0)) from employees
2 Creating Groups of Data
  1)
  a Divide rows in a table into smaller groups by using the group by clause
  b All coulmns in the select list that are not in group function must be in the group by clause
  select department_id,avg(salary)
  from employees
  group by department_id;
  2) Grouping by More Than One Column
  3) Ilegal Queries Using Group Functions
   a You cannot use thee where clause to restrict groups
   b You use thee having clause to restrict groups
   c you cannot use group functions in the where clause
  4)Excluding Group Resdults:The Having Clause
   Use the HAVING clause to restrict groups
   a Rows are grouped
   b The group functions is applied
   c Groups matcching the Having clause are display
  select department_id,max(salary)
  from employees
  group by department_id
  having max(salary)>10000
 5) Nesting Group function
 select max(avg(salary))
 from employees
 group by department_id;

posted @ 2006-09-22 11:49 康文 阅读(197) | 评论 (0) | 编辑 收藏

window programming --keybord.txt

1 Keyboardd Basics
 1) Ignoring the Keyboard
 Your programm does not need to act on every keyboard message it received,Window handle many keyboard message function itself.
 2)Who's Got thefocus
  Though the keyboard is shared by all the window in the application ,The DispatchMessage send the message to the window procedure associated the window which message is intended.
  The window that receives a particular keyboard event is the window has the input foucs.
  Sometime no window has input foucs,this is the case if all your programs have been minmized,window continue send keyboard to the active window ,but it is send in the deffert form from sending to the input foucs.
  A window procedure can be determine when its window has the input focus by trapping WM_SETFOCUS and WM_KILLFOCUS.
 3) Queues and Synchronization
  As the user presses and releases key on keyborad,Windows and keyboard device driver translate the hardware scan code into formatted message.Howerver the messages are not palced on the application queue right away,Instean Windows store these message in a system message queue .The System message queue is a single message maintained by windows specifically for the prelimary storage of user input from keyboard and the mouse. Window will take the next message from the system message queue and place it on the application message queue only when a window application has finished proecssing the previous user input message.
4) Keystorkes and Character
 The message that an application receives from windows about keyboard events distingush between keystrokes and characters.
 for instance The keysokes has only one key labbed 'A' ,and the character may be 'a' or 'ctr-a' etc.
2 Keystroke Message
 1)Wirtual key Codes
  The virtual key code is stored in the wParam parameter of WM_KEYDOWN,WM_KEYUP,the code identifies the key being pressed or release.
  2)lParam Information
  the wParam message parameter contain virtual key code and the lparam message parameter contains other information in understanding the keystoke.
  3) Shift States
  iState = GetKeyState (VK_SHIFT) ;
  iState variable will be negative if the Shift key is donw
  iState = GetKeyState (VK_CAPITAL) ;
  4)Using Keystroke Messages
   
  5)
   case WM_KEYDOWN:
     switch (wParam)
     {
     case VK_HOME:
          SendMessage (hwnd, WM_VSCROLL, SB_TOP, 0) ;
          break ;

     case VK_END:
          SendMessage (hwnd, WM_VSCROLL, SB_BOTTOM, 0) ;
          break ;

     case VK_PRIOR:
          SendMessage (hwnd, WM_VSCROLL, SB_PAGEUP, 0) ;
          break ;
3 Character Messages
Message Key or Code
WM_KEYDOWN Virtual key code for `A' (0x41)
WM_CHAR Character code for `a' (0x61)
WM_KEYUP Virtual key code for `A' (0x41)

Message Key or Code
WM_KEYDOWN Virtual key code VK_SHIFT (0x10)
WM_KEYDOWN Virtual key code for `A' (0x41)
WM_CHAR Character code for `A' (0x41)
WM_KEYUP Virtual key code for `A' (0x41)
WM_KEYUP Virtual key code VK_SHIFT (0x10)

Key Character Code Duplicated by ANSI C  Escape
Backspace     0x08 Ctrl-H                \b
Tab           0x09 Ctrl-I                \t
Ctrl-Enter    0x0A Ctrl-J                \n
Enter         0x0D Ctrl-M                 \r
Esc 0x1B Ctrl-[

  case WM_CHAR:
     [other program lines]
     switch (wParam)
     {
     case `\b':          // backspace
          [other program line
          break ;
     case `\t':          // tab
          [other program lines]
          break ;

     case `\n':          // linefeed
          [other program lines]
          break ;

     case `\r':          // carriage return
          [other program lines]
          break ;

     default:            // character codes
          [other program lines]
          break ;
     }
     return 0 ;

posted @ 2006-09-19 18:25 康文 阅读(275) | 评论 (0) | 编辑 收藏

windows programming --window and message

1 An Architectural Overview
  1)Getting a good feel for messages is an import part of learning how to write programs for windows.
  Windows send a message to your porgram means that Windows calls a function in your program .The parameter of this function describe the message that is being send.The function in your program is know as Window Procedure.
  Windows send a message to window by calling window procedure ,The window procedure do some processing based on the message and return control to Windows.
  More precisely , a Window  is always createdd based on a "window class".The window class identifies the window procedure that precesses messages to the windows.The use of window class allow mutiple window to be based the same window class and hence use the same window procedure.
  2) Requsteriing the Window Class
 typedef struct
 {
     UINT        style ;
     WNDPROC     lpfnWndProc ;
     int         cbClsExtra ;
     int         cbWndExtra ;
     HINSTANCE   hInstance ;
     HICON       hIcon ;
     HCURSOR     hCursor ;
     HBRUSH      hbrBackground ;
     LPCTSTR     lpszMenuName ;
     LPCTSTR     lpszClassName ;
 }
 if (!RegisterClass (&wndclass))
 {
     MessageBox (NULL, TEXT ("This program requires Windows NT!"),
                 szAppName, MB_ICONERROR) ;
     return 0 ;
 }
 2)Creating the Window
  Window class define the general Characteristics of the a window.If you want to create window based on the same window class,you can use CreateWindwo which allow you to specify more detail imformation about the window.
  hwnd = CreateWindow (szAppName,                  // window class name
                     TEXT ("The Hello Program"), // window caption
                     WS_OVERLAPPEDWINDOW,        // window style
                     CW_USEDEFAULT,              // initial x position
                     CW_USEDEFAULT,              // initial y position
                     CW_USEDEFAULT,              // initial x size
                     CW_USEDEFAULT,              // initial y size
                     NULL,                       // parent window handle
                     NULL,                       // window menu handle
                     hInstance,                  // program instance handle
                     NULL) ;                     // creation parameters

 3)Displaying the window
   When thee CreateWindow function return ,windows create a window internal.What it means is that windows allocate a block memory to store the imformation about the window.If you want to show that ,you should call
ShowWindow (hwnd, iCmdShow) ;
UpdateWindow (hwnd) ; 
 4) The Message Loop
 while (GetMessage (&msg, NULL, 0, 0))
 {
     TranslateMessage (&msg) ;
     DispatchMessage (&msg) ;
 }

 typedef struct tagMSG
{
     HWND   hwnd ;
     UINT   message ;// message identifier
     WPARAM wParam ;
     LPARAM lParam ;
     DWORD  time ; // the time the message is placed on the message queen
     POINT  pt ; // the mouse coordiante
 }
 typedef struct tagPOINT
 {
     LONG  x ;
     LONG  y ;
 }
POINT, * PPOINT;
the message filed of message retrived from the message queen is anyting except WM_QUITm ,GetMessage return a nonzero value
wM_QUIT cause GetMessage reuturn 0.

TranslateMessage (&msg) ;
passing the msg struct back to window for some keysboard translation

DispatchMessage (&msg) ;
pass the msessageback to window .Windwo then send the message to the appropriate window procedure for processing.After window
procedure processing the message ,it return control to the windows,which is still in serving the Dispatchmessage
 5) The Window Procedure
  a The window procedure determined the how the window display on the client area and how the window respose to user input
  b LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam),the four parameter is idential to the first four filed of the message struct.
 6) Processing the Message
 switch (iMsg)
{
case WM_CREATE :
     [process WM_CREATE message]
     return 0 ;
         
case WM_PAINT :
     [process WM_PAINT message]
     return 0 ;
         
case WM_DESTROY :
     [process WM_DESTROY message]
     return 0 ;
}
return DefWindowProc (hwnd, iMsg, wParam, lParam) ;

when a window procedure process the message ,it should return 0;
 7) The WM_PAINT Message
  WU_PAINT message is extremely import in window.it inform a program when part or all of the window 's client area are invalid and must be redraw or repaint.
 WM_PAINT processing almost always begins with a call to BeginPaint:
  hdc = BeginPaint (hwnd, &ps) ; //return a handle to device context
and ends with a call to EndPaint:
 EndPaint (hwnd, &ps) ;
 8)The WM_DESTROY Message
  PostQuitMessage (0) ;
  
 WNDCLASS, * PWNDCLASS ;
 #include <windows.h>
/* the same as long _stdcall WndPro(long,unsign int,unsign int ,long)*/
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

/*int _stdcall WinMain(long hInstance,long hPrevInstance,char * szComdLine,int iCmdShow)*/
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,   
                    PSTR szCmdLine, int iCmdShow)
{
     static TCHAR szAppName[] = TEXT ("HelloWin") ;
     HWND         hwnd ;
     MSG          msg ;
     WNDCLASS     wndclass ;
/*
  all window createe based on this window class will completely repaint whenever  horizational window sizd and vertial  
  window size change.
*/
     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;                 
     wndclass.lpfnWndProc   = WndProc ; // set the window procedure for the window class
     wndclass.cbClsExtra    = 0 ;
     wndclass.cbWndExtra    = 0 ;
     wndclass.hInstance     = hInstance ; // the handle of this program
     wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;
     wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;
     wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
     wndclass.lpszMenuName  = NULL ;
     wndclass.lpszClassName = szAppName ;

     if (!RegisterClass (&wndclass))
     {
          MessageBox (NULL, TEXT ("This program requires Windows NT!"),
                      szAppName, MB_ICONERROR) ;
          return 0 ;
     }
     hwnd = CreateWindow (szAppName,                  // window class name
                          TEXT ("The Hello Program"), // window caption
                          WS_OVERLAPPEDWINDOW,        // window style
                          CW_USEDEFAULT,              // initial x position
                          CW_USEDEFAULT,              // initial y position
                          CW_USEDEFAULT,              // initial x size
                          CW_USEDEFAULT,              // initial y size
                          NULL,                       // parent window handle
                          NULL,                       // window menu handle
                          hInstance,                  // program instance handle
                          NULL) ;                     // creation parameters
    
     ShowWindow (hwnd, iCmdShow) ;// iCmdShow determine how the window is to be initially displayed on the screen.
     UpdateWindow (hwnd) ; // cause the client area to paint
    
     while (GetMessage (&msg, NULL, 0, 0))
     {
          TranslateMessage (&msg) ;
          DispatchMessage (&msg) ;
     }
     return msg.wParam ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     HDC         hdc ;
     PAINTSTRUCT ps ;
     RECT        rect ;
    
     switch (message)
     {
     case WM_CREATE:
          PlaySound (TEXT ("hellowin.wav"), NULL, SND_FILENAME | SND_ASYNC) ;
          return 0 ;

     case WM_PAINT:
          hdc = BeginPaint (hwnd, &ps) ;//return a handle to device context
         
          GetClientRect (hwnd, &rect) ;// set the struct rect with the dimensions of the client area
         
          DrawText (hdc, TEXT ("Hello, Windows 98!"), -1, &rect,
                    DT_SINGLELINE | DT_CENTER | DT_VCENTER) ;
          EndPaint (hwnd, &ps) ;
          return 0 ;
         
     case WM_DESTROY:
          PostQuitMessage (0) ;// insert a WM_QIUT in the message queue.
          return 0 ;
     }
     return DefWindowProc (hwnd, message, wParam, lParam) ;
}

2 The Window Programming Hurdles
 1)Queue and noqueue message
  queue message are post the message queue and the noqueue message send to the window procdure directly.
    

posted @ 2006-09-18 09:17 康文 阅读(255) | 评论 (0) | 编辑 收藏

Spring -transaction

1 Understand Transaction
  1) Introduce Spring's transaction manager
  a  JDBC transactions 
     <bean id="transactionManager" class="org.springframework.jdbc.
      datasource.DataSourceTransactionManager">
     <property name="dataSource">
     <ref bean="dataSource"/>
     </property>
     </bean>
   b Hibernate transactions
     <bean id="transactionManager" class="org.springframework.
       orm.hibernate.HibernateTransactionManager">
     <property name="sessionFactory">
     <ref bean="sessionFactory"/>
     </property>
     </bean>
2 Programing transaction in Spring
   One approach to adding transaction to your code is to programmly add transactional boundary using transiationTemplate class.
   Programming is good when you want complete control over transactional boundary.but you have to use spring specific class.In most case ,your tansactional needs will not require such precise control over transactional boundaries.That is why you will typically choolse to declare transaction support
  public void enrollStudentInCourse() {
    transactionTemplate.execute(
    new TransactionCallback() {
      public Object doInTransaction(TransactionStatus ts) {
        try {
          // do stuff   Runs within doInTransaction()
        } catch (Exception e) {
          ts.setRollbackOnly(); //Calls setRollbackOnly() to roll Calls setRollbackOnly()                                 //to roll back
        }
          return null;   //If successful, transaction is committed
      }
    }
   );
 }
 <bean id="transactionTemplate" class="org.springframework.
       transaction.support.TransactionTemplate">
  <property name="transactionManager">
    <ref bean="transactionManager"/>
  </property>
 </bean>
 <bean id="courseService"
    class="com.springinaction.training.service.CourseServiceImpl">
 <property name=" transactionTemplate">
     <ref bean=" transactionTemplate"/>
   </property>
 </bean>
3 Declaring transactions
  Spring's support for declarative transaction management is implementedd through Spirng's  AOP framework.
  <bean id="courseService" class="org.springframework.transaction.
       interceptor.TransactionProxyFactoryBean">
  <property name="proxyInterfaces">
    <list>
      <value>
        com.springinaction.training.service.CourseService  
      </value>
    </list>
  </property>
  <property name="target">
   <ref bean="courseServiceTarget"/>   //Bean being proxied
  </property>
 <property name="transactionManager">
   <ref bean="transactionManager"/>   //Transaction manager
 </property>
 <property name="transactionAttributeSource">
   <ref bean="attributeSource"/>   //Transaction attribute source
 </property>
 </bean>
 1) Understanding transaction attributes
  In Spring transaction attribute is a description of how transaction policies should be
applied to a methods
   a  Propagation behavior
    Propagation behavior                 What it means
    PROPAGATION_MANDATORY                indicate that the method must run within a                                                  transaction.If no transaction is in progress
                                         an exception will be thrown
    PROPAGATION_NESTED
    PROPAGATION_NEVER                    indicate that the method can not run withi a                                                transaction. if a transaction exist an exception                                            will be thrown.
    PROPAGATIOM_NOT_SUPPORT              Indicates that the method should not run within a                                           transaction. If an existing transaction is                                                  in progress, it will be suspended for the
                                         duration of the method.
    PROPAGATION_REQUIRED                 indicate that the current method must run within a                                          transaction.if an existing transaction is in                                                progress,the ,method will run with the transaction
                                         otherwise a new transaction will be started
    PROPAGATION_REQUIRENEW               indicates that the current must run within its own
                                         transaction.A new transaction is started and an                                             existing transaction will be suspend
    PROPAGATION_SUPPORT                  indicate the current mehtod does not require a                                          transaction.but may run if on is already in progress     
    b Isolation levels     
    Isolation level                    What it means
    ISOLATION_DEFAULT                  Using the defaul isolation level of the underlying                                          database
    ISOLATION_READ_UNCOMMITTED         Allows you read change that have not yet been commit
                                       May result in dirty read,phantom read,nonrepeatable                                         read
    ISOLATION_READ_COMMITTED           Allows reads from concurrent transactions that have
                                       bean committed.Dirty read are prevent.but platform                                          and norepeatable reads may still occur.
    ISOLATIOM_REPEATABLE_READ          Multiple read the same field will yield the same                                            result ,unless changed by the transaction                                                   itself.Dirty reads ,nonrepeatable are all prevented
                                       phantom may still occur
    ISOLATION_SERIALIZABLE             This fully ACID-compliant isolation level ensusme                                        that dirty read,unrepeatable read ,phantom read are                                        all prevented.And this is the most slowest isolation
                                       since it is typically accomplished by doing full                                        table lock on the tables in the transaction.

   c Read-Only
   If a transaction performs only read operation against the underlying datastore.when a transaction begin ,it only make sense to declare a transaction as read only on mehtods with
propagation behavior which start a new transaction.
   Furthermore ,if you are Hibernate as persistence mechanism,declaring a transaction as read only will reult in Hibernate flush mode being set to FLUST_NEVER.this tell hibernate to avoid synchroniztion of objects with database.
   d Transaction timeout
   Suppose that your transaction becomes unexpectedly long-running transaction.Because transaction may invole locks on the underlying database.Instead of waiting it out ,you can delcare a transaction to automaitically roll back.
   because timeout clock begin ticking when a transaction start. it only make sense to declare a transaction timeout on methods with propagation behavior that start a new transaction.
  2) Declaring a simple transaction policy
   <bean id="myTransactionAttribute"
    class="org.springframework.transaction.interceptor.
            DefaultTransactionAttribute">
  <property name="propagationBehaviorName">
    <value>PROPAGATION_REQUIRES_NEW</value>
  </property>
  <property name="isolationLevelName">
    <value>ISOLATION_REPEATABLE_READ</value>
  </property>
 </bean>
 <bean id="transactionAttributeSource"
    class="org.springframework.transaction.interceptor.
            MatchAlwaysTransactionAttributeSource">
  <property name="transactionAttribute">
    <ref bean="myTransactionAttribute"/>
  </property>
 </bean>
4 Declaring transactions by method name
  1) Using NameMatchTransactionAttributeSource
  The properties property of NameMatchTransactionAttributeSource maps mehtod to a transaction property descriptor. the property descriptor takes the following form:
  Propagation,isolation,readOnly,-Exception,+Exception
 
  <bean id="transactionAttributeSource"
    class="org.springframework.transaction.interceptor.
            NameMatchTransactionAttributeSource">
  <property name="properties">
    <props>
      <prop key="enrollStudentInCourse">
          PROPAGATION_REQUIRES_NEW
      </prop>
    </props>
  </property>
 </bean>
 2) Specifying the transaction Isolation level
  <bean id="transactionAttributeSource"
    class="org.springframework.transaction.interceptor.
            NameMatchTransactionAttributeSource">
     <property name="properties">
    <props>
      <prop key="enrollStudentInCourse">
        PROPAGATION_REQUIRES_NEW,ISOLATION_REPEATABLE_READ
      </prop>
    </props>
  </property>
 </bean>
 3) Using real-only transaction
  <bean id="transactionAttributeSource"
    class="org.springframework.transaction.interceptor.
            NameMatchTransactionAttributeSource">
  <property name="properties">
    <props>
      <prop key="getCompletedCourses">
        PROPAGATION_REQUIRED,ISOLATION_REPEATABLE_READ,readOnly
      </prop>
    </props>
  </property>
</bean>
 4)Specifying  rollback rules
  You can sepcify that a transaction be rollback on specify checked exception
  <bean id="transactionAttributeSource"
    class="org.springframework.transaction.interceptor.
            NameMatchTransactionAttributeSource">
  <property name="properties">
    <props>
      <prop key="enrollStudentInCourse">
        PROPAGATION_REQUIRES_NEW,ISOLATION_REPEATABLE_READ,
        -CourseException
        </prop>
     </props>
    </property>
  </bean>
  Exception can be marked as negative(-) or postive(+)
  Negative exception will trigger the roll back if the exception (or sublclass of it) is thrown.Postive exception on the other hand indicate that the transacton should be commit
even if the exception is thrown
 5)Using wildcard matches
 <bean id="transactionAttributeSource"
    class="org.springframework.transaction.interceptor.
            NameMatchTransactionAttributeSource">
  <property name="properties">
    <props>
      <prop key="get*">
        PROPAGATION_SUPPORTS
      </prop>
    </props>
  </property>
</bean>
 6 Short-cut name match transaction
 <bean id="courseService" class="org.springframework.transaction.
       interceptor.TransactionProxyFactoryBean">
   <property name="transactionProperties">
    <props>
      <prop key="enrollStudentInCourse">
        PROPAGATION_REQUIRES_NEW
      </prop>
    </props>
   </property>
 </bean>

posted @ 2006-09-15 11:00 康文 阅读(1798) | 评论 (0) | 编辑 收藏

window programming --Unicode

一 Unicode 简介
 1 Unicode 是ASCII 扩展，从传统的7位，扩展位16 位，可以显示世界上所有语言
ASCII 码
       0-     1-     2-     3-     4-     5-     6-     7-
-0     NUL    DLE    SP     0      @      P      `      p
-1     SOH    DC1    !      1      A      Q      a      q
-2     STX    DC2    "      2      B      R      b      r
-3     ETX    DC3    #      3      C      S      c      s
-4     EOT    DC4    $      4      D      T      d      t
-5     ENQ    NAK    %      5      E      U      e      u
-6     ACK    SYN    &      6      F      V      f      v
-7     BEL    ETB    '      7      G      W      g      w
-8     BS     CAN    (      8      H      X      h      x
-9     HT     EM     )      9      I      Y      I      y
-A     LF     SUB    *      :      J      Z      j      z
-B     VT     ESC    +      ;      K      [      k      {
-C     FF     FS     ,      <      L      \      l      |
-D     CR     GS     -      =      M      ]      m      }
-E     SO     RS     .      >      N      ^      n      ~
-F     SI     US     /      ?      O      _      o      DEL

 2 双位字符集
DBCS：double-byte character set，最初的128个代码是ASCII，较高的128个代码中的某些总是跟随著第

二个位元组。这两个位元组一起（称作首位元组和跟随位元组）定义一个字元。

 3 Unicode 解决方案
  Unicode是统一的16位元系统，也DBCS 这样的同时含有一位和两位的字符集不同，Unicode 可以表示

65536 个字符。
  Unicode 的缺点是，Unicode 使用的空间是ASCII 的两倍
二 宽字符和c
 1 char
  char c='A';
  变量c 用一个字节来存储，用16 进制表示位0x41
  char * p;
  32 位系统，一次指针变量需要用4个字节表示
  char * p="Hello!";
  字符串占用7个字节 其中 6个用于保存字符串，1个用于保存中止符号0
  char [10]
  占用10个字节
  char a[]="Hello!";
  占用 7个字节
 2 宽字节
  typedef unsigned short whcar_t   which is define in the window.h 
  与unsign short 一样 为16 字节，两个字节
  wchar_t c='A'   0x0041
  wchar_t *p=L"Hello!"  指针占用 4个字节 而 字符串占用 14 个字节
 3 宽字元程序库函数
  char * pc = "Hello!" ;
  iLength = strlen (pc) ;
  wchar_t * pw = L"Hello!" ;
  iLength = wcslen (pw) ;
 4 维护单一原始码
 Microsoft Visual C++包含的TCHAR.H
 如果定义了名为_UNICODE的识别字，并且程式中包含了TCHAR.H表头档案，那么_tcslen就定义为wcslen
 #define _tcslen wcslen
 如果没有定义UNICODE，则_tcslen定义为strlen：
 #define _tcslen strlen
 如果定义了 _UNICODE识别字，那么TCHAR就是wchar_t：
 typedef wchar_t TCHAR ;
 否则，TCHAR就是char：
 typedef char TCHAR ;

 如果没有定义_UNICODE识别字
 #define __T(x) x
 #define _T（x） __T（x）
 #define _TEXT（x） __T（x）

三 宽字节和windows
  1 window 头文件中的类型
  typedef char CHAR ;
  typedef wchar_t WCHAR ；
  typedef CHAR * PCHAR, * LPCH, * PCH, * NPSTR, * LPSTR, * PSTR ;
  typedef CONST CHAR * LPCCH, * PCCH, * LPCSTR, * PCSTR ;
  typedef WCHAR * PWCHAR, * LPWCH, * PWCH, * NWPSTR, * LPWSTR, * PWSTR ;
  typedef CONST WCHAR * LPCWCH, * PCWCH, * LPCWSTR, * PCWSTR ;

  #ifdef  UNICODE                  
  typedef WCHAR TCHAR, * PTCHAR ;
  typedef LPWSTR LPTCH, PTCH, PTSTR, LPTSTR ;
  typedef LPCWSTR LPCTSTR ;
  #else
  typedef char TCHAR, * PTCHAR ;
  typedef LPSTR LPTCH, PTCH, PTSTR, LPTSTR ;
  typedef LPCSTR LPCTSTR ;
  #endif
  2 Windows 函数调用
  #ifdef UNICODE
  #define MessageBox  MessageBoxW
  #else
  #define MessageBox  MessageBoxA
  #endif
  3 Windows 的字符函数
  ILength = lstrlen (pString) ;
  pString = lstrcpy (pString1, pString2) ;
  pString = lstrcpyn (pString1, pString2, iCount) ;
  pString = lstrcat (pString1, pString2) ;
  iComp = lstrcmp (pString1, pString2) ;
  iComp = lstrcmpi (pString1, pString2) ;
  4 在windows 使用printf
   windows 并不支持printf 但是可以使用sprintf
   int printf (const char * szFormat, ...) ;
   printf ("The sum of %i and %i is %i", 5, 3, 5+3) ;
   int sprintf (char * szBuffer, const char * szFormat, ...) ;
   char szBuffer [100] ;
   sprintf (szBuffer, "The sum of %i and %i is %i", 5, 3, 5+3) ;
   puts (szBuffer) ;

posted @ 2006-09-14 15:12 康文 阅读(219) | 评论 (0) | 编辑 收藏

spring -database

一 Spring DAO philosophy
 1 Understanding Spring's DataAccesssException
 Spring's DAO frameworks donot throw teechnology-specific exceptions such as SQLException
or HibernateeExcepiton.Instead ,all exceptions thrown are subclasses of DataAccessException
 2 You are not forced to handle DataAccessExceptions
 DataAccessException is a RuntimeException,so it si an unchecked exception.Since these are quite often unrecoverable,you are not forced to handle these exception.
  Instead ,you can catch the exception if recovery is possible.since DataAccessException is not only a RuntimeException,but it subclasses Spring's NestedRuntimeException. This menas that the root Exception is alwarys via NestedRuntimeException's getCause() method.
 3 Work with DataSources
  a getting a Datasource from JNDI
   <bean id="dataSource"
      class="org.springframework.jndi.JndiObjectFactoryBean">
   <property name="jndiName">
    <value>java:comp/env/jdbc/myDatasource</value>
   </property>
   </bean>
  b Creating a Datasource connection pool
   <bean id="dataSource"
      class="org.apache.commons.dbcp.BasicDataSource">
  <property name="driver">
    <value>${db.driver}</value>
  </property>
  <property name="url">
    <value>${db.url}</value>
  </property>
  <property name="username">
    <value>${db.username}</value>
  </property>
  <property name="password">
    <value>${db.password}</value>
  </property>
</bean>
 c Using a DataSource while testing
  DriverManagerDataSource dataSource = new DriverManagerDataSource();
  dataSource.setDriverClassName(driver);
  dataSource.setUrl(url);
  dataSource.setUsername(username);
  dataSource.setPassword(password);
 4 Consistent DAO support
  Spring template class handle the invariant part of data access-controling the trancsaction
manage resource,handling exception .Implementation of callback interface define what is specific to your application--creating statement,binding parameter and marshalling result set.
 Spring separates the fixed an vaiant parts of data access process into tow distince classes:
template and callbacks.Template manage the fixed parts of the process while callback are where you fill in the implement details;
 one the top of template-callback desing ,spring framework provide a support class which your own data access subclass it. And the support class already have a property for holding a template.
 二 Integerating Hibernate with Spring
  1 Managing Hibernate resources
   you will keep a single instance of SessionFactory throughtout your application
   <bean id="sessionFactory"class="org.springframework.
           orm.hibernate.LocalSessionFactoryBean">
     <bean id="sessionFactory" class="org.springframework.
       orm.hibernate.LocalSessionFactoryBean">
     <property name="dataSource">
       <ref bean="dataSource"/>
     </property>
  </bean>
  you also want to manager how hibernate is configured
  <bean id="sessionFactory" class="org.springframework.
       orm.hibernate.LocalSessionFactoryBean">
  <property name="hibernateProperties">
    <props>
      <prop key="hibernate.dialect">net.sf.hibernate.
           dialect.MySQLDialect</prop>

    </props>
  </property>
  …
 </bean>
 and the last thing is whick map files is read
  <bean id="sessionFactory" class="org.springframework.
       orm.hibernate.LocalSessionFactoryBean">
  <property name="mappingResources">
     <list>
     <value>Student.hbm.xml</value>
     <value>Course.hbm.xml</value>
     …
   </list>
  </property>
     …
  </bean>

 Now  you have fully configured your sessionfactory ,so we need do create an object which we
will access hibernate. As we know, we will use a template class
  <bean id="hibernateTemplate"
      class="org.springframework.orm.hibernate.HibernateTemplate">
  <property name="sessionFactory">
    <ref bean="sessionFactory"/>
  </property>
 </bean>

  <bean id="courseDao" class="com.springinaction.
       training.dao.hibernate.CourseDaoHibernate">
  <property name="hibernateTemplate">
    <ref bean="hibernateTemplate"/>
  </property>
 </bean>

 2 Accessing Hibernate through HibernatTemplate
  The template-callback mechanism in Hibernatee is pretty simple.There is the HibernatTmpplate and one callback interface
  public Student getStudent(final Integer id) {
  return (Student) hibernateTemplate.execute(
    new HibernateCallback() {
      public Object doInHibernate(Session session)
          throws HibernateException {
        return session.load(Student.class, id);
      }
    });
 
  The HibernateTemplate class provides some convience methods that implicit create a HibernateCallback instance:
  (Student) hibernateTemplate.load(Student.class, id);
   hibernateTemplate.update(student);
  hibernateTemplate.find("from Student student " +
                                "where student.lastName = ?",
                                lastName, Hibernate.STRING);
  3 Subclassing HibernateDaoSupport
  public class StudentDaoHibernate extends HibernateDaoSupport
    implements StudentDao {
  …
  }
  getHibernateTemplate()
  getSession()

posted @ 2006-09-14 11:45 康文 阅读(265) | 评论 (0) | 编辑 收藏

hibernate 一级缓存

1 hibernate 一级缓存
Session 
  evict(Object o) 从缓存中清除指定的持久化对象
  clear()         清除缓存中所有对象
2 批量更新于批量删除
  1) 批量更新
   Iterator customers=session.find("from Customer c where c.age>0");
   while(customers.hasNext()){
     Customer customer=(Customer)customers.next();
     customer.setAge(customer.getAge()+1);
   }
   tx.commit();
   session.close();

  缺点：内存中加载了大量数据
        执行了多次update 语句
 
   改进
   Iterator customers=session.find("from Customer c where c.age>0");
   while(customers.hasNext()){
     Customer customer=(Customer)customers.next();
     customer.setAge(customer.getAge()+1);
     session.flush();
     session.evict(customer);
   }
   tx.commit();
   session.close();
   遗留问题
   执行了多次update 语句
  
   采用jdbc api 进行调用
   Connection con=session.connection();
   PrepareStatement stmt=con.prepareStatement("update customers set age=age+1 where age>0");
   stmt.executeUpdate();
   tx.commit();
   另外，也可以调用底层的存储过程进行批量更新
   create or replace procedure batchUpdateCustomer(p_age,in number) as
   begin
      update customer set age=age+1 where age>p_age;
   end;
  
   tx=session.beginTransaction();
   Connection con=session.connection();
   CallableStatement cstmt=con.prepareCall(batchUpdateCustomer);
   cstmt.setInt(1,0);
   cstmt.eqecuteUpdate();
   tx.commit();
   2) 批量数据的删除
    session.delete("from  Customer c where c.age>0");
    实际调用的过程
    session * from Customer where age>0;
    在把所有数据加载到内存之后执行多条delete 语句
    delete from customer where id=i;
     .......................
   改进办法采用jdbc api 进行批量数据的删除
     
   tx=session.beginTransaction();
   Connection con=session.connection();
   con.execute("delete from customers where age>0");
   tx.commit();

posted @ 2006-09-14 09:22 康文 阅读(463) | 评论 (0) | 编辑 收藏

hibernate -类型

Hibernate                  java                     sql                    oracle       

integer or int             int or Integer           INTEGER
long                       long or Long             BIGINT
short                      short or Short           SMALLINT
byte                       byte or Byte             TINYINT
float                      float or Float           FLOAT
double                     double or Double         DOUBLE
big_decimal                java.math.BigDecimal     NUMBERBIC
character                  char java.lang.Character CHAR(1)
                           String                     
string                     String                    VARCHAR
boolean                    boolean or Boolean        BIT
date                       java.util.Date            DATE
                           java.sql.Date
time                       Date or java.sql.time     TIME
timestamp                  Date or java.sql.Timestamp TIMESTAMP              
binary                     byte[]                    blog                   blog
text                       String                    clob                   clog
serializable                                         blog                   blog            
clob                       java.sql.clob            clob                    clob
blob                       java.sql.blob             blog                   blob

posted @ 2006-09-14 09:20 康文 阅读(327) | 评论 (0) | 编辑 收藏

windows programming -jump from start.txt

1 动态连接
Windows 运作机制的核心是一个称作动态连接的概念

#include <windows.h>
int WINAPI WinMain ( HINSTANCE hInstance, HINSTANCE hPrevInstance,
   PSTR szCmdLine, int iCmdShow)
{
MessageBox (NULL, TEXT ("Hello, Windows 98!"), TEXT ("HelloMsg"), 0);
return 0 ;
}

 1) #include <windows.h>包含其它的头文件
 2) 程序入口
   int WINAPI WinMain （ HINSTANCE hInstance,HINSTANCE hPrevInstance,
             PSTR szCmdLine,int iCmdShow）

   a #define WINAPI __stdcall  指定一个呼叫约定，包括如何生产机器码，参数如何入栈
   b HINSTANCE hInstance 执行体代号，唯一标识该程序
   c HINSTANCE hPrevInstance 已经不采用
   d PSTR szCmdLine 参数列表
   e int iCmdShow 显示方式
  3) MessageBox 函数
   MessageBox (NULL, TEXT ("Hello, Windows 98!"), TEXT ("HelloMsg"), 0);
   参数1 窗体代号
   参数2 主题显示文字
   参数3 标题显示文字
   参数4 按钮，0 为确认 使用C语言的OR（|）操作符号将上面显示的一个常数与代表内定按钮的常数组合：

 
#define  MB_OK                           0x00000000L
#define  MB_OKCANCEL                     0x00000001L
#define  MB_ABORTRETRYIGNORE             0x00000002L
#define  MB_YESNOCANCEL                  0x00000003L
#define  MB_YESNO                        0x00000004L
#define  MB_RETRYCANCEL 

#define  MB_DEFBUTTON1                   0x00000000L
#define  MB_DEFBUTTON2                   0x00000100L
#define  MB_DEFBUTTON3                   0x00000200L
#define  MB_DEFBUTTON4

图示的外观
#define  MB_ICONHAND                        0x00000010L
#define  MB_ICONQUESTION                       0x00000020L
#define  MB_ICONEXCLAMATION                    0x00000030L
#define  MB_ICONASTERISK

#define  MB_ICONWARNING               MB_ICONEXCLAMATION
#define  MB_ICONERROR                 MB_ICONHAND
#define  MB_ICONINFORMATION           MB_ICONASTERISK
#define  MB_ICONSTOP

2 c 语言编译过程 c--compile --   .obj   ---linking----  .exe

posted @ 2006-09-13 16:37 康文 阅读(215) | 评论 (0) | 编辑 收藏

c++ builder 文件的操作

一 文件
   1 c 标准文件驱动器，可以支持两种文件类型，二进制文件，和文本文件。c 标准文件是在头文件

stdio.h 中声明。
标准文件类型通过指针来进行存储 FILE * fp;
   2 c++ 流式文件类 fstream，ifstream 和ofstream，分别对应读写，读和写，并支持文本和二进制文

件。
   3 非缓冲文件
二 文件对话框组件
   1 OpenDialog 两种.TXT and .PAS 两种类型的过滤器。
     1) Filter OpenDaalog1->Filter="Text files{*.txt}|*.TXT|Pascal files{*.pas}|*.PAS";
  同一个过滤器中，还可以有多种文件后缀
      OpenDialog1->Filter="Pascal files|*.PAS;*.DPK;*.DPR";
     2) FilterIndex 设置对话框一打开时选中的文件过滤。数值从1开始计算。
     3) InitialDir 设置对话框打开时定位的目录。
     4) Options
       OpenPictureDialog1->Options.Clear();
       OeenPictureDialog1->Options<<ofFileMustExist<<ofHideReadOnly<<ofNoChangeDir;
     5) Title 设置对话框标题中显示的内容。
   2 SaveDialog 组建可以选择并保存文件
   3 OpenPictureDialog 可以选择并打开图形文件。
   4 SavePictureDialog 可以选择并保存图形文件。
三 Win3。1 相关组件
   FileListBox，DirectoryListBox，DriveCombox,FilterComboBox
四 常用文件管理函数
  1 文件函数常用函数
  将一个文件从记录盘上删除，如果不存在或无法删除。则返回False。
  extern PACKAGE bool __fastcall DeleteFile(const AnsiString FileName);
  void __fastcall TFORM1::ButtonClick(TObject *Sender)
  {
      char buffer[256];
      GetWindowsDirectory(buffer,sizeof(buffer));//获取Windows 系统目录
     AnsiString asFileName=FileSearch(Edit1->Text,GetCurrentDir()+AnsiString(";")

+AnsiString(buffer));//在当前目录下和windows系统}//目录下查询文件。 
  if(asFileName.IsEmty()) ShowMessage(AnsiString("Couldn't Found")+Edit1->Text1);
  2 FileSeek
  extern PACKAGE int __fastcall FileSeek(int Handle, int Offset, int Origin);
  extern PACKAGE __int64 __fastcall FileSeek(int Handle, const __int64 Offset, int Origin);

  Description

  Use FileSeek to reposition the read/write point in a file that was opened with FileOpen or

FileCreate. Handle is the file handle that was returned by FileOpen or FileCreate.

  Offset specifies the number of bytes from Origin where the file pointer should be

positioned. Origin is a code with three possible values, denoting the beginning of the file,
  the end of the file, and the current position of the file pointer.

  Origin Action

  0 The file pointer is positioned Offset bytes from the beginning of the file.
  1 The file pointer is positioned Offset bytes from its current position.
  2 The file pointer is positioned Offset bytes from the end of the file.

  If FileSeek is successful, it returns the new position of the file pointer; otherwise, it

returns -1.
   void __fastcall TForm1::Button1Click(TObject *Sender)

{
  int iFileHandle;
  int iFileLength;
  int iBytesRead;
  char *pszBuffer;
  if (OpenDialog1->Execute())
  {
    try
    {
      iFileHandle = FileOpen(OpenDialog1->FileName, fmOpenRead);
      iFileLength = FileSeek(iFileHandle,0,2);
      FileSeek(iFileHandle,0,0);
      pszBuffer = newchar[iFileLength+1];
      iBytesRead = FileRead(iFileHandle, pszBuffer, iFileLength);
      FileClose(iFileHandle);

      for (int i=0;i<iBytesRead;i++)
      {
        StringGrid1->RowCount += 1;
        StringGrid1->Cells[1][i+1] = pszBuffer[i];
        StringGrid1->Cells[2][i+1] = IntToStr((int)pszBuffer[i]);
      }
      delete [] pszBuffer;
    }
    catch(...)
    {
      Application->MessageBox("Can't perform one of the following file operations: Open,

Seek, Read, Close.", "File Error", IDOK);
    }
  }
}
 3FileExists
  if(FileExist(SaveDialog1->FileName))
 {
   RenameFile(SaveDialog1->File,SaveDialog1->FileName+".bak");
 }
 iFileHandle=fileCreate(SaveSialog1->FileName);
 for(int i=0;i<Memo2->Lines->String[i].length())
 {
   FileWrite(iFileHandle,Memo2->Lines->String[i].c_str(),length);
 }
 FileClose(iFileHandle);
  4 FileGetAttrs
  FileGetAttr returns the attributes of the file as a string of bits. This value is the same

as the Attr field of a TSearchRec struct. Check for individual attributes with code such as

the following:
  int Attrs = FileGetAttr("MyFile.sys");
  if x(Attrs & faHidden)
  FileSetAttr("MyFile.sys", Attrs & !faHidden);
  A return value of -1 indicates that an error occurred.
  5 FileSetAttrs
  FileSetAttr sets the file attributes of the file given by FileName to the value given by

Attr. The value of Attr is formed by combining the appropriate file attribute constants, as

in the following:
  FileSetAttr("MyFile.sys", faReadOnly | faSysFile);
  FileSetAttr returns zero if the function was successful. Otherwise the return value is an

error code.
三 目录操作常用函数
  1 CreateDir
     #include <Filectrl.hpp>
   void __fastcall TForm1::Button1Click(TObject *Sender)

   {
      if (!DirectoryExists("c:\\temp"))
      {
            if (!CreateDir("C:\\temp"))
            throw Exception("Cannot create c:\\temp directory.");
      }
   }
   2 ForceDirectories
   ForceDirectories creates a new directory as specified in Dir, which must be a fully-

qualified path name. If the directories given in the path do not yet exist, ForceDirectories

attempts to create them.
   ForceDirectories returns true if it successfully creates all necessary directories, false

if it could not create a needed directory.
   Important
   Do not call ForceDirectories with an empty string. Doing so causes ForceDirectories to

throw an exception. 
   void __fastcall TForm1::Button1Click(TObject *Sender)
   {
         AnsiString Dir = "C:\Apps\Sales\Local";
         if (ForceDirectories(Dir))
         Label1->Caption = Dir + " was created";
   }
   3 GetCurrentDir
   获取当前的目录完整的路径名
   4 RemoveDir
   删除一个存在的目录，目录必须为空
   5 SetCurrentDir设置系统的当前目录
   6 SelectDirectory
   extern PACKAGE bool __fastcall SelectDirectory(constAnsiString Caption, const WideString

Root, AnsiString &Directory);
   Call SelectDirectory to let the user enter a directory name.  
   Use the first syntax to display the Windows directory browser. The Caption parameter

specifies a caption for the dialog. The Root parameter specifies the root directory from

which to browse. The selected directory is returned as the Directory parameter. When using

this syntax,
   SelectDirectory does not change the value of the current directory.
  
   extern PACKAGE bool __fastcall SelectDirectory(AnsiString &Directory, TSelectDirOpts

Options, int HelpCtx);
   enum TSelectDirOpt { sdAllowCreate, sdPerformCreate, sdPrompt };
   typedef Set<TSelectDirOpt, sdAllowCreate, sdPrompt>  TSelectDirOpts;
  
   sdAllowCreate An edit box allows the user to type in the name of a directory that
                        does not exist. This option does not create a directory: the

application
                        must read the name of the selected directory and create it i
                      f desired.
   sdPerformCreate Used only in combination with sdAllowCreate. If the user enters a

directory
                        name that does not exist, the directory selection dialog creates it.
   sdPrompt        Used only in combination with sdAllowCreate. Displays a message box
                       that informs the user when the entered directory does not exist
                       and asks if the directory should be created.
                       If the user chooses OK, the directory is created
                       if the option set includes sdPerformCreate.
                       If the option set does not include sdPerformCreate,
                       the directory is not created:
                the application must read the directory name and create
    #include <FileCtrl.hpp>
    void __fastcall TForm1::Button1Click(TObject *Sender)
   {
      AnsiString Dir = "C:\\Program Files\\MyApp";
      if (SelectDirectory(Dir, TSelectDirOpts() << sdAllowCreate << sdPerformCreate <<

sdPrompt,1000))
      Label1->Caption = Dir;

   }
三 驱动器常用函数
  1 DiskFree 指定驱动器中剩余空间的字节数
  2 DiskSize 驱动器容量
四文件名常用函数
  1 ChangeFileExt
  2 ExtractFileDir
  3 ExtractFileDriver
  4 ExtractFileExt
  5 ExtractFileName
  6 ExtractFilePath
  7 ExtractRelativePath
实例
1
   1
L a b e l 1 目录列表( & D ) : FocusControl: DirectoryListBox1
D i r e c t o r y L i s t B o x 1 D i r L a b e l : L a b e l 6 ;
                                                    FileList: FileListBox1
L a b e l 2 文件列表( & S ) : FocusControl: FileListBox1
F i l e L i s t B o x 1 FileEdit: Edit1
L a b e l 3 驱动器( & R ) : FocusControl: DriveComboBox1
D r i v e C o m b o B o x 1 DirList: DirectoryListBox1
L a b e l 4 文件类型( & F ) : FocusControl: FilterComboBox1
F i l t e r C o m b o B o x 1 FileList: FileListBox1
      Filter: 所有文件 ( * . * ) | * . * |文本文件( * . t x t ) | * . t x t
L a b e l 5 路径名：
L a b e l 6 C : \ S a m p l e s \ S 0 6 B
L a b e l 7 文件名( & N ) : FocusControl: Edit1
E d i t 1
B u t t o n 1 文件长度( & L ) . . . Te x t : * . *
#include<stdio.h>
void __fastcall TForm1::Button1Click(TObject *Sender)
{
FILE* fp;
AnsiString FileFullName;
long size;
AnsiString PropertyMes;
FileFullName=Label2->Caption+"\\"+Edit1->Text;
if(FileExists(FileFullName))
{
  fp=fopen(FileFullName.c_str(),"rt");
  if(fp!=NULL)
  {
    fseek(fp,0L,SEEK_END);
    size=ftell(fp);//get the length of file
    PropertyMes="file is total"+IntToStr(size)+"bytes.";
    MessageDlg(PropertyMes,mtInformation,TMsgDlgButtons() << mbOK, 0);

  }else
  {
      MessageDlg(PropertyMes,mtWarning,TMsgDlgButtons() << mbOK, 0);
  }
  fclose(fp);
 }
}

 2 获取驱动器类型信息
 UINT GetDriveType(
  LPCTSTR lpRootPathName //获取根目录的路径名称
 )
 
表6-5   函数G e t D r i v e Ty p e的返回值及其含义
数 值                             含 义
0                            无法检测驱动器的类型
1                             根目录不存在
D R I V E _ R E M O VA B L E 可移动驱动器
D R I V E _ F I X E D 不可移动驱动器
D R I V E _ R E M O T E 网络驱动器
D R I V E _ C D R O M C D - R O M驱动器
D R I V E _ R A M D I S K 虚拟驱动器

Result=GetDriveType(Edit2->Text.c_str());
3 操作ini 文件

posted @ 2006-09-09 23:25 康文 阅读(2955) | 评论 (0) | 编辑 收藏

动态链接库

动态连接库（Dynamic link library）,是一些编译过的可以执行的代码模块，后缀为.dll
1 DLL的基本理论
  在使用普通函数库时，可以在程序连接时将库中的代码拷贝到执行文件中，这时静态链接，在多个同样程序执行时，体统保留了许多
代码副本，造成了内存资源的浪费。在使用dll时，不必将dll链接到程序中，而是在应用程序运行时动态的装载dll，装载dll被映射
到进程的地址空间中。同时，使用dll 并不时将库代码拷贝，只是在程序中记录了函数的入口点和接口。
2 DLL 的优点
 1） 节省系统资源
 2） 不仅可以包括可执行代码，还可以包括数据和各种资源
 3）支持多语言
 4）升级可以仅仅覆盖dll 文件
 5）dll 独立编程语言，c++builder 中的dll vc 也可以使用
3导入导出匹配
    DLL函数一般有两种函数，内部函数（internal）和导出函数(export).在实际情况下，许多DLL 调用了其他DLL里面的函数，因此
DLL可以同时有导入和导出函数。
     DLL 包含有一个导出函数表，可以通过函数的符号化的名字和称为序号的正书来识别这些函数，函数表中包含了函数在dll内部的
地址。在动态链接进程好建立一张表，把客户的调用与dll里的函数的地址连接起来。
    double dbValue(value);//内部函数
    double dbValue(value);//内部函数
    extern"c" _declspec(dllexpoert) double changeValue(double,bool);//外部函数
   double dblValue(double value)
   {
       return value*vlaue;
   }
   double changeValue(double value,bool whichOp)
  {
     return whichOp?doublValue(value):halfValue(value);
   }
  如果我们希望dll可以用于其他语言或不同版本的c++ 需要在声明导出函数的时候加上extern "C."
 4 隐式的链接和显示的链接
   隐式链接（前面所讲）在创建dll 的时候，链接器产生一个lib 文件把拿获了dll中的导出符号和序号
   显示链接调用Win32 的LoadLibrary 函数，使用完后，调用 FreeLibrary.
 5 查找dll
   依次顺序为包含exe 的目录，进程的当前目录，Windows 目录，path 环境变量里列出的目录。
 6 创建动态链接库
   （如何查看dll 文件的定义）
 7 导出函数：extern "C" __declspec(dllexport) ExportType FunctionName(Parameter)
    extern "C" __declspec(dllimport) __stdcall void CreateFromFunct();
    extern "C" __declspec(dllexport) __stdcall void CreateFromFunct();//导出函数
    导出类：class __declspec(dllexport) ExportType ClassName{...}
    class __declspec(dllexport) __stdcall MyDllClass { //导出类
     public:
    MyDllClass();
    void CreateAForm();
    TDllFrm* DllMyForm;
    };

     __declspec(dllimport) class __stdcall MyDllClass {
       public:
       MyDllClass();
       void CreateAForm();
       TDllFrm* DllMyForm;
    };
    静态调用，build 生成dll 文件和lib 文件，并把lib 文件导入到工程中
     void __fastcall TForm1::Button1Click(TObject *Sender)
    { // 导出类实现，导出类只能使用静态方式调用
       DllClass = new MyDllClass();
       DllClass->CreateAForm();  
    }
    void __fastcall TForm1::Button2Click(TObject *Sender)
    { // 导出函数实现
       CreateFromFunct();
     }
     void __fastcall TForm1::FormClose(TObject *Sender, TCloseAction &Action)
    {
         delete DllClass;
     }
   动态调用
   class TForm1 : public TForm
  {
         ...
      private: // User declarations
      void (__stdcall *CreateFromFunct)();
           ...
   }
  HINSTANCE DLLInst = NULL;
  void __fastcall TForm1::Button2Click(TObject *Sender)
  {  
     if( NULL == DLLInst ) DLLInst = LoadLibrary("DLL.dll"); //上面的 Dll
     if (DLLInst) {
             CreateFromFunct = (void (__stdcall*)()) GetProcAddress(DLLInst,
                          "CreateFromFunct");
      if (CreateFromFunct) CreateFromFunct();
      else ShowMessage("Could not obtain function pointer");
   }
      else ShowMessage("Could not load DLL.dll");
  }
   void __fastcall TForm1::FormClose(TObject *Sender, TCloseAction &Action)
  {
     if ( DLLInst ) FreeLibrary (DLLInst);
  }
8  bcb 调用vc 编写的DLL
  1） 名字分解
   1. 名字分解：
  没有名字分解的函数
    TestFunction1 // __cdecl calling convention
    @TestFunction2 // __fastcall calling convention
    TESTFUNCTION3 // __pascal calling convention
    TestFunction4 // __stdcall calling convention
  有名字分解的函数
    @TestFunction1$QV // __cdecl calling convention
    @TestFunction2$qv // __fastcall calling convention
    TESTFUNCTION3$qqrv // __apscal calling convention
    @TestFunction4$qqrv // __stdcall calling convention
  使用 extern "C" 不会分解函数名
   2）
      __cdecl 缺省
   是 Borland C++ 的缺省的 C 格式命名约定，它在标识符前加一下划线，以保留
  它原来所有的全程标识符。参数按最右边参数优先的原则传递给栈，然后清栈。
    extaern "C" bool __cdecl TestFunction();
   在 def 文件中显示为
    TestFunction @1
   注释： @1 表示函数的顺序数，将在“使用别名”时使用。

  __pascal Pascal格式
   这时函数名全部变成大写，第一个参数先压栈，然后清栈。
    TESTFUNCTION @1 //def file

  __stdcall 标准调用
   最后一个参数先压栈，然后清栈。
    TestFunction @1 //def file

  __fastcall 把参数传递给寄存器
   第一个参数先压栈，然后清栈。
    @TestFunction @1 //def file
  3）
   3. 解决调用约定：
   Microsoft 与 Borland 的 __stdcall 之间的区别是命名方式。 Borland 采用
  __stdcall 的方式去掉了名字起前的下划线。 Microsoft 则是在前加上下划线，在
  后加上 @ ，再后跟为栈保留的字节数。字节数取决于参数在栈所占的空间。每一个
  参数都舍入为 4 的倍数加起来。这种 Miocrosoft 的 DLL 与系统的 DLL 不一样。
 4 查看dll 的调用接口tdump -ee MyDll.dll >1.txt (查看 1.txt 文件即可)
5 编辑c++ builder build 为一个可以直接调用的 .exe 。 点击project option  中linker 标签 去掉user dynamic RTL 选项 和package 中 去掉builder with runtime package 选项.
6 调用代参数的vl 编写的dll 调用的实例。
int (__cdecl *fun)(char*,char*,char*);

HINSTANCE DLLInst = NULL;
void __fastcall TForm1::Button1Click(TObject *Sender)
{
if( NULL == DLLInst )
{
DLLInst = LoadLibrary("HollyIVRCard.dll");
}
if(DLLInst)
{
  fun=(int (__cdecl*)(char*,char*,char*))GetProcAddress(DLLInst,"hTrade");
  if(fun)
  {
    cardid=Edit1->Text.c_str();
    num=Edit2->Text.c_str();
    ShowMessage(fun(cardid,num,res));
    //cout<<cardid<<endl;
    //cout<<num<<endl;
  }
} else{
   ShowMessage("load dll fail");
}
   ShowMessage(AnsiString(res));
}

posted @ 2006-09-06 18:13 康文 阅读(380) | 评论 (0) | 编辑 收藏

spring --wiring binding

Containing your beans
    Tere i sno single Spring container.Spring actually comes with two distince types of containers:Bean factories and Application

contexts.Beyong there two basic types of contains .Srping come with sereral implementss of BeanFacotory and ApplicationContext.
  1 introducing the BeanFactory
  There are several implementations of BeanFactory in Spring .But the most userful one is XmlBeanFactory,whick loads
its bean based on the definitions contained in an xml file.
  Creat a XmlBeanFactory  BeanFactory factory=new XMLBeanFactory(new FileInputStream("beans.xml"));
 But at that time ,the BeanFactory does not initialize the bean ,it is loaded lazliy.
  Get the Bean :MyBean myBean=(MyBean)factory.getBean("myBean");
 When getBean() is called ,the factory will instantiate the bean and being setting the bean using dependency injection.
  2 Working with an application context
 an ApplicationContextis prefered over a BeanFactory in nearly all application ,the only time you might consider using a BeanFactory

are in circumtance where resource s are scarce.
   Amony the many implements of ApplicationContext are three that are commonly used:
      ClassPathXmlApplicationContext,FileSystemXmpApplicationContext,XmlWebApplicationContext.
   ApplicationContext context=new ClassPathXmlApplicationContext("foo.xml");
 wiring the beans
  <beans>
    <bean id="foo" class="com.springinaction.Foo" />
 </beans>
 Prototyping vs.singleton
 By default ,all Spring beans are singletons.When the container dispenses a bean it will always give the exact same instance of the    

In this case ,you would want to define a prototype bean .Defining a prototype means that instead of defining a single bean.
     <bean id="foo" class="com.springinaction.Foo"  single/>on="false" />
Initialization and destruction
   <bean id="foo" class="com.springinaction.Foo" init-method="setup" destory-method="teardown">
Injectiong dependencies via setter method
   <bean id="foo" class="com.srpinginaction.Foo" >
        <property name="name">Foo McFoo</value>
   </bean>
 Referencing other beans
   <bean id="foo" class="com.springinaction.Foo">
     <property name="bar" >
        <ref bean="bar" />
     </property>
    </bean>
    <bean id="bar" colass="com.srpinginaction.Bar" />
 Inner beans
   <bean id="courseService"
             class="com.CourseWericeImpl">
     <property nanme="studentService">
         <bean
              class="com....." />
      </property>
   </bean>
  Wiring collections
    1Wiring lists and arrays  java.util.List
      <property name="barList">
           <list>
                <value>bar1</value>
                <ref bean="bar2"/>
           </lsit>
      </property>
   2 Wiring set  java.tuil.Set
    <property name="barSet">
          <set>
                 <value>bar1</value>
                 <ref bean="bar2" />
          </set>
   </property>
   3 Wiring maps java.util.Map
   <property name="barMap">
        <ebtry key="key1">
        <value>bar1</value>
   </property>
  4 Wiring propertyies
    <property name="barProps">
         <props>
            <prop key="key1">bar1</prop>
            <prop key="key2">bar2</prop>
         </props>
    </property>
  5 Setting null values
   <property name="foo"><null/><property>
   injecting dependencies via constructor
   <id="foo" class="com.springinaction.Foo">
    <constructor-arg>
        <value>42<value>( <ref bean="bar">)
     </constructor-arg>
    <bean id="foo" class="com.springinaction.Foo">
       <constructor-arg>
            <value>http://www.manning.com</value>
       </constructor-arg>
  <constructor-arg>
            <value>http://www.manning.com</value>
       </constructor-arg>
   </bean>

posted @ 2006-09-04 11:10 康文 阅读(306) | 评论 (0) | 编辑 收藏

代码会生锈吗？

posted @ 2006-08-30 11:14 康文 阅读(252) | 评论 (0) | 编辑 收藏

关于软件小组矩阵式管理的一点点想法

posted @ 2006-08-28 16:39 康文 阅读(511) | 评论 (0) | 编辑 收藏

对需求分析中的一些想法

posted @ 2006-08-27 08:23 康文 阅读(256) | 评论 (0) | 编辑 收藏

c++ 速成

    用了几年java 了，突然想学习c++ ,昨天用了一天的时间疯狂的学习了一天c++ 基础知识，发现感觉还不错，不过精验告诉我，学编程语言一定要实践，在这里指记录了一些学习中的点滴。

  1 const 与volatile 的用法
  1 const
   #include<conio.h>
   #include<iostream.h>
   //行参数指向const 类型变量的指针
   void display_c(cons int * pi)
   {
     cout<<"display_c:"<<*pi<<endl;
   }
   //行参为普通类型变量的指针
   void display(int *pi)
   {
     cout<<"display_c:"<<*pi<<endl;
   }
   //const 类型变量
   const int i1=1;
   //error  i1=3;
   //const 类型变量的指针
   int i2=2;
   const int * pi2=&i2;
   //error *pi2=3
   // const 指针
   int * const pi3=&i3;
   *pi3=5;
   // error *pi3=&i4  可以赋予不同的值，但是不可一指向不同的变量
   //指向const 内容的const 指针
   const int * cosnt pi5=&i5;
2 sizeof 返回某个便赖宁嘎或数据类型的长度
3 引用
 1 引用变量
  int i=1;
  int & r_i=i;
5 名空间
  1 namespace
   namespace car
  {
    int model;
    int length;
    int width;
  }
  namespace plane
  {
    int model;
    namespace size
    {
      int lenth;
      int width;
    }
  }
  namespace car //添加名空间的成员
  {
    char * name;
  }
  namespqce c=car; //定义别名
  int Time //外不变量属于全局名空间
 
  car::length=3;
  plane::size::length=70;
 
  int Time=1996;
  ::Time=1997;

 2 using
  void main()
 {
   using namespace car;
   length;
   using namespace phane;
   model;

 }
6 new 与delete 运算符
 double * pd;   // define pointer variable
 pd=new double; // allocate memory
 if(pd!=null)
 {
   ...
  delete pd;  // free memory
 }

 double1=null
 * pds=new double[100];
 if(pds)
 {
   ....
  delete[] pds;

 }

 如果是使用new 进行内存空间分配没有成功，则返回空指针null
 释放一个数组分配的内存是，常常采用带[]的形式
7 void 指针 它指向一个地址值，但是不说名数据类型，可以使用void 指针创建一个通用的函数，在使用
 的时候将指针类型转化成相应的具体类型。
 void ShowHex(void *pv,int siae)
{
 ....
 ((unsigned char *)pv)[i]
}
void main()
{
  void *pv=null;
  unsigned char c1=0x12;
  pv=&c1;
  ShowHex(pv,sizeof(c1));
 }
9 typeid 运算符 用来求得变量或队形爱女嘎的数据类型，返回一个type_info 类型的对象，通过该对象
  可以获取数据类型的名称

  include<typeinfo.h>
  int i;
  const type_info &t0=typeid(i);
  t0.name();
10 函数
   1 模板函数
  template<class T> T min(R &x,Tv&y)
 {
   return x<y?x:y;
 }
  2 指向函数的指针
   int max(int x,int y)
  {
    ...
  }
  int min(int x,int y)
  {
     ...
  }
  int (* m_pfunction)(int,int);
  void main()
  {
    m_pfunction=max;
    (*m_pfunction)(2,3);
     m_pfunction=min;
    (*m_pfunction)(2,3);
  }
11 类与对象
 1 构在函数和析构函数
 #include <iostream.h>
#include <string.h>
#include <conio.h>
class Book
{
private:
  char * pBookName;
public:
  int PageNum;
public:
  Book(char * pBN=NULL);
  ~ B o o k ( v o i d ) ;
  void SetBookName(char * pBN);
  int GetBookName(char * pBN,unsigned int MaxSize);
} ;

Book:Book(char *PBN)
{
  cout<<"构造函数"<<endl;
  pBookName=null;
  if(oBN!=null)
  {
     pBookName=new char[strlen(pBN)+1];
     if(pBookName!=null)
         strcyp(pBookName,pBN);
  }
}

Book::~Book()
{
  delete[] pBookName;
}

void Book::SetBookName(char * pBN)
{
  if(pBookName！＝null)
    delete[] pBookName;
   pBookName=new char[strlen(pBN)+1];
     if(pBookName!=null)
         strcyp(pBookName,pBN);
}

int Book::GetBookName(char * pBN,unsigned intmaxSize)
{
 if((pBookName!=null))&&(MaxSize>strlen(pBookName))
{
  strcpy(pBN,pBookName);
  retrun strlen(strlen(pBookName));
 }
}

// 使用
Book b1;
b1.SetBookName("test");
Book b2(test1);
 2 对象的引用参数传递
  void Add(Book b)
  void AddRef(Book & b);
 3 静态成员变量 是一个公共变量
 在初始化 的时候利用作用运算符:: 对私有类型的静态成员变量可以向公有类型的静态成变量一样赋值
 但不能直接引用
 3 const 类型成员函数与mutable
 class CDate
 {
   public:
    int year;
    mutable int month;
    CDate(int y=2000,int m=1)
    {
       year=y;
       month=m;
    };
    int BetMonth() const ;//read only
    void SetMonth(int m);// write only
 }
  void CDate::SetMonth(int m)
 {
   month=m;
 }
 void main()
 {
   CDate d1;
  
 }

 在const 类型的成员函数定义中，不可一直接或简介的修改普通类型的成员变量
 如果象修改const 类型对象的成员函数，可以使用关键字mutable 对该成员变量进行修改
 5 对象的初始化与初始化行
 将参数类表中的数值赋予成员变量时，不仅可以在构造函数的函数体中进行，以阿宽衣在初始化行中进行
 在初始化处惊醒初始化的情况有：
  1 分层类的构在函数可以调用它的任何一个子对象的构造函数
  2 对常量const 类型的成员变量的初始化必须在初始化行上
  3 对于引用类型的成员变量的初始化必须在初始化行上
 
 class CPoint
 {
   public：
    int x,y;
    CPoint(int ax=0,int ay=0)
    {
      x=ax;
      y=ay;
    }
 };

 class CRect
 {
   private:
    CPoint low_right;
    CPoint up_left;
   public:
    int & CenterX;
    const int CenterY;
    CRect(int x1,int y1,int x2,int y2,int &x3,int y3)
     :up_left(x1,y1),low_right(x2,y2),CenterX(x3),CenterY(y3)
   {
    
   }
 };
void main()
{
  int cx=5;
  int cy=6;
  CRect r1(1,2,3,4,cx,cy);
}
 6 拷贝构造函数
  拷贝构造函数与普通构造函数的差别在与棋参数类表，参数列表中有一个对象，该对象的数据类型是
 本类的一个引用，而且一般情况下，该对象还应该是一个const 类型的对象。
  如果在类的定义是不是显示的定义一个拷贝函数，则编译器会自动的定义一个拷贝构造函数
 
 class CPoint
 {
   public:
     int x,y;
     CPoint(int m_x=0,ubt m_y=0);   // default constructor 
     cPoint(const CPoint &c);      //copy consrucotr
 };
 CPoint::CPoint(int m_x,int m_y)
 {
  
 }
 
 CPoint::CPoint(const CPoint &c)
 {
   x=c.y;
   y=c.x;
 }

 void main()
 {
   CPoint c1(1,2);  //invoke default constructor
   CPoint c2-c1;    // invoke copy constructor
 }
7 template class
 template<class t,int Size>class Array // template class
 {
   private:
     T arr[Size];
     int CurSize;
   public:
    Array(T * date,int n)
    {
      CurSize=n<Size?n;Size;
      for(int i=0;i<CurSize;i++)
      {
        Arr[i]=data[i]; 
      }
    }
}

void main()
{
  int i1[10]={1,2,3,4,5,6,7,8,9};
  Array<int,6>array_i1(i1,i0);
}

1 友员类和友员函数
  #include <iostream.h>
  #include<string.h>
  #include<conio.h>

class SoftWareEngineer; //先对SoftwareEngineer 类进行显示说明一下

class Computer // 定义Computer 类
{
   private:
     int Price;
   public:
     Computer(int p){Price=p};
    friend class SoftwareEngineer; //将友员类载这里声明
    frined void Judge(Computer &c,SoftwareEngineer  & s) //友员函数
   
}；

class SoftwareEngineer
{
   int Salary;
   char Name[20];
  public:
    SoftwareEngineer(int s,char *n //构造函数)
  {
     Salary=s;
     strcpy(Name,n);
  }
int GetComputerPrice(Computer &c){return c.Price} //访问Computer 的思友变量
friend void Judge(Computer &c,SoftwareEngineer & s) //友员函数
}；
//判断一个软件工程师是否可以用一个月的薪水买的器一台电脑
void Judge(Computer &c,SoftwareEngineer &s) //桥友员函数
{
   if(c.Price>s.Salary)
     cout<<"软件工程师"<<s.Name<<"的一个月薪水买不起一台电脑"<<endl;
   else
     cout<<"软件工程师"<<s.Name<<"的一月薪水买的起一台电脑"<<endl;
}
void main()
{
  Computer c1(100);
SoftwareEngineer s1(120,"user1");
Judge(c1,s1);

SiftwareEngineer s2(80,"user2")
Judge(c1,s2);
getch();
}
2运算符重载
#include<iostream.h>
#include<conio.h>
#include<iomanip.h>

class TValue{
 private:
     int value;
 public:
   TValue(int i){value=i}
 //成员函数重载运算符
  TValue operator!();
  TValue operator+(TValue & rv);
 // 友员函数重载运算符
  friend ostream & operator<<{ostream & os,TValue & rv};
}

TValue Tvalue::operator!()
{
  return TValue(!value);
}

TValue TValue:operator+(TValue& rv)
{
  return TValue(value+rv.value);
}

ostream & operator<<(ostream & os,TValue rv)
{
   os<<setw(5)<<rv.value;
  return os;
}

void main()
{
   TValue v1(3),v2(5);
   cout<<
}
3 类的派生和继承
1class Box{
   public:
     int width,height;
     void SetWidth(int w){width=w};
     void SetWidth(int h){height=h;};
 };
 class TColorBox::public Box{
  public:
     int color;
     void SetColor(int c){color=c;};
 };

void main(){
    TColorBox cb;
    cb.SetColor(255); //声明非继承类的对象
    cb.SetWidth(100);//声明继承类的对象
    cb.SetHeight(100); //声明继承类的对象
  
  }
 2 不能被继承的成员
  构造函数，析构函数，用户定义的新操作符，用户定义的赋值操作，友员关系
 3 构造函数，析构函数的调用顺序
class A{
 int a,b,c;
 public:
  A(int x,int y,int z)
{
   a=x;
   b=y;
  c=z;
}

};
class B{
  int d;
  public :
   B(int xx):A(xx,xx+1,xx+2)(d=xx);//内联构造函数
   B(int x,int y,int z,int xx);//非内联构造函数
  B:B(int x,int y,int z,int xx):A(x,y,z)
{
   d=xx;
}
}
 
实例
class Currency
{
  poublic:
    double par_value;
    Currency(){per_value=0.0;}
    Currency(double d){per_value=d;}
    Currency(Currency &rc){par_value=rc.par_value;}
  
   Currency & operator={Currency & c}
   {
      par_valuc=c.par_value;
      return * this;
   }
   Currency & operator+(Currency & c)
  {
     par_value+=c.par_value;
    return *this;
  }
}

//人民币
 class RMB:public Currency
 {
   public:
   RMB():Currency(){};//调用派生类的构造函数前，需要调用器基类的工造函数
   RMB(double d):Currency(d){};
   RMB(Currency& c)：Currency(c){};
   RMB(RMB& rmb):Currency(rnb){};
   friend ostream& operator<<{ostream& os,RMB& rnb};//派生类的附加功能
 }；
 ostream& operator<<{ostream& os, RMB& rmb} //output 运算符不能是一个类的成员函数
{
  os<<"￥"<<setiosflags(ios::shwopoint|ios:fixed)<<setprecision(2)rmb.par_value;
 return os;
}

void main()
{
   RMB r_income(5000);
   RMB r_balance;
   r_balance=r_income=r_expense;
  cout<<"income"<<r_income<<endl;
}
4 将iostream 运算符重载
 1)ostream & operator<< (ostream &os,const Triangular & ths)
{
   os<<"("<<rhs.beg_pos()<<","<<rhs.length()<<")";
  rhs.display(rhs.length(),rhs.beg_pos(),os);
}
ouutput 运算符不能够设计成member function
 2)istream& operator>>(istream &is,Triangular &rhs)
 {
    char ch1,ch2;
    int bp,len;
   //输入 ch1='(',bp=3,ch3=',' len=6
   is>>ch1>>bp>>ch2>>len;
   rhs.beg_pos(bp);
   rhs.length(len);
   rhs.next_reset();
   return is;
 }
Triangular tris;
cin>>tri2
4 虚基类
载继承关系中，同一基类被继承多次，不仅会引器歧异，而起可能浪费空间
 class A
{
   public:
     int value;
};
class B:public virtual A(); //虚基类 编译器只产生一个基类版本。如果不定义为virtual 编译器不知到调用那个value 了，当然
class C:public virtual A();//  也可以return B::value;
class D:public b.public c
{
  public
   int GetValue(){return value;}
};

void main()
{
  D dd;
  dd.GetValue();
}

5 多态形，和虚函数
class TFirst
{
   public virtual void Display();
};

void TFirst::Display()
{
   cout<<"first "
}

class TSecond:public TFirst
{
   public:
     virtual void Display();
};

void TSecond::Display()
{
   cout<<"second"
}

void Display(TRist * pFirst)
{
   pFisrt=>Display();
}

void main()
{
   TFirst * pFirst=new TFirst;
   TSecond * pSecond=new TSecond;
   pFirst->Display();
   pSecond->Display();
   Display(pFirst);
   Display(pSecond);
    delet pfirst ；
    delet pSecond;
  
    getch();
}

c++ builder 中的集合的
  1 集合的概念基本
   Set<type,minval,maxval>
   Set<char,'A','C'> s1
  
   tydefef Set(char,1,255) UPPERCASet;
   UPPERCASESet s1;
   s1<<'A'<<'B'<<'C';
   sysset.h 直接包含载vcl.h 中
  2 集合的操作
   #include<iostream>
   #include<system.hpp>
   #include<conio.h>
  
   using namespace std;
  typedef Set<char,'B','Z'> UpperSet;
  typedef Set<char,'a','z'> LoverSet;
  typeder Set<char,'a','j'> HalfLowerSet;

  void set_example()
  {
      LowerSet ae,ae2,ac,de;
      UpperSet AE,AE2,AC,DE;
     HalfLowerSet aj;
  }

异常处理
1 c++ 的异常处理
 #include <iostream.h>
 #include <conio.h>

 class Crange
 {
    public:
      int index;
      CRange(int i){index=i;}
}
   class CString
   {
        char a[100];
        int len;
        public:
         CString(char * s)
        {
             Len=strlen(s);
             strcpy(a,s);
        } 
       char & operator[](int i)
      {
           if(i>0 && i<len) return a[i];
           else throw CRange(i);
      }
    
      void DisplayNoCatch(CString & s)
     {
             int j;
             for(j=0lj<20;j++)
               cout<<s[j]<<""endl;;
     }
   
     int DisplayHasCatch(CString & s)
    {
        try{
               DisplayNoCatch(s);
        }catch(CRange r)
        {
                cerr<<r.index<<endl;
        }
         return 99;
    }
 }
 2 多路捕捉
  #include<iostream.h>
  #include<conio.h>
  void MultiException()
  {
      int i;
      double d;
    
      int no;
      cout<<"(>0 and <5)";
      cin>>no;
      tyr
      {
         switch(no)
        {
            case 1;
               throw 123;
               break;
             case 2:
               throw i;
               break;
             case 3:
               throw d;
               break;
             case 4:
               throw "Error";
                break;
              default:
                cout<<"error";
        }
      }
      catch(int ie)
     {
          cout<<"int"<<endl;
     }
     catch(double de)
     {
         cout<<"double"<<endl;
     }
     catch(char* se)
    {
          cout<<"char"<<endl;
    }
  }

 3 bcb中的异常类
   1)却省vcl 异常处理 无try catch 自动处理
     int i=4,j=0;k;
     k=i/k;
     //下一句永远不会执行
    ShowMessage(k);
   2) 引发vcl 异常类
    try{
    }
    catch(Exception &e)
    {
          ShowMessage(e.,Message);
    }
   不能引发如int double 等简单类型的异常
   3) c++ 异常处理
    try
    {
         throw 2222;
    }
    catch(int ErrorCode)
   {
         ShowMessage(ErrorCode);
    }
 }
 4 单一捕捉异常
   try{
      k=10/0;
   }catch(EDivByZero & E)
   {
      MessageDlg() 
   }
  5 捕捉所有异常
   try
   {
   }catch(...) or(EExternalException &E)

posted @ 2006-08-25 15:28 康文 阅读(2551) | 评论 (0) | 编辑 收藏