1. hsql 学习
1.1. 学习目的
本文档是针对hSQL 数据库方面的基础学习，为了使项目组成员能够达到使用hSQL 数据库的目的。
1.2. 培训对象
开发人员
1.3. 常用词及符号说明
常用词：
hsql：一种免费的跨平台的数据库系统
E:\hsqldb：表示是在dos 命令窗口下面
1.4. 参考信息
doc\guide\guide.pdf
2. HSQL
2.1. HSQL 运行工具
java -cp ../lib/hsqldb.jar org.hsqldb.util.DatabaseManager
注意hsqldb.jar 文件的文件路径,最好能放到classpath 里面,或者放到当前路径下.
java -cp hsqldb.jar org.hsqldb.util.DatabaseManager
2.2. 运行数据库
启动方式: Server Modes and
In-Process Mode (also called Standalone Mode).
一个test 数据库会包含如下文件:
? test.properties
? test.script
? test.log
? test.data
? test.backup
test.properties 文件包含关于数据库的一般设置.
test.script 文件包含表和其它数据库,插入没有缓存表的数据.
test.log 文件包含当前数据库的变更.
test.data 文件包含缓存表的数据
test.backup 文件是最近持久化状态的表的数据文件的压缩备份文件
所有以上这个文件都是必要的,不能被删除.如果数据库没有缓存表,test.data 和test.backup 文件将不会存在.另外,除了以上文件HSQLDB 数据库可以链接到任何文本文件,比如cvs 文件.
当操作test 数据库的时候, test.log 用于保存数据的变更. 当正常SHUTDOWN,这个文件将被删除. 否则(不是正常shutdown),这个文件将用于再次启动的时候,重做这些变更.test.lck 文件也用于记录打开的数据库的事实, 正常SHUTDOWN,文件也被删除.在一些情况下,test.data.old 文件会被创建,并删除以前的.
2.3. Server Mode
java -cp ../lib/hsqldb.jar org.hsqldb.Server -database.0 file:mydb -dbname.0 xdb
命令行方式:
启动数据,数据库文件mydb,数据库名称xdb
也可以在 server.properties 文件中定义启动的数据库,最多10个
例如: server.properties:
server.database.0=file:E:/hsqldb/data/mydb
server.dbname.0=xdb
server.database.1=file:E:/hsqldb/data/testdb
server.dbname.1=testdb
server.database.2=mem:adatabase
server.dbname.2=quickdb
启动命令: java -cp ../lib/hsqldb.jar org.hsqldb.Server
运行结果如下
java 测试程序:
package test;
import junit.framework.TestCase;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class TestConnect extends TestCase {
Connection connection;
protected void setUp()
{
try {
Class.forName("org.hsqldb.jdbcDriver" );
connection = DriverManager.getConnection("jdbc:hsqldb:hsql://localhost/xdb","sa","");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void testselect()
{
Statement stmt=null;
ResultSet rs=null;
try {
stmt = connection.createStatement();
String sql ="select * from test";
rs=stmt.executeQuery( sql);
while(rs.next() )
{
System.out.println("id="+rs.getString("id"));
System.out.println("name="+rs.getString("name"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
try {
rs.close() ;
stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
protected void tearDown()
{
try {
connection.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
以上在eclipse 中测试通过.
2.4.In-Process (Standalone) Mode
不需要启动server
connection = DriverManager.getConnection("jdbc:hsqldb:file:E:/hsqldb/data/mydb","sa","");
这样就可以连接数据库。
只能在一个jvm 中使用，不能在多个jvm 中使用。
这种模式是在相同的jvm 下作为你的应用程序的一部分，运行数据库引擎。对大多数应用程序，这种模式运行会相当快，作为数据，不需要转换和网络传输。
主要的缺点就是不可能从外面的应用程序访问到默认数据库，因此当你的应用运行时候，你不能通过别的工具检查数据库内容。在1.8.0 版本中,你可以在相同jvm 中的线程中运行数据库初始化，并提供外面访问你的进程内数据库。
推荐在开发应用中使用这种方式。
连接串：
Windows: DriverManager.getConnection("jdbc:hsqldb:file:E:/hsqldb/data/mydb","sa","");
Unix: DriverManager.getConnection("jdbc:hsqldb:file:/opt/db/testdb","sa","");
2.5.Memory-Only Databases
当随即访问内存，数据库不固定时，可以采用内存的方式运行数据库，由于没有数据写到硬盘上，这种方式使用在应用数据和applets 和特殊应用的内部进程中使用，URL：
Connection c = DriverManager.getConnection("jdbc:hsqldb:mem:aname", "sa", "");
2.6.Using Multiple Databases in One JVM
2.7.Different Types of Tables
HSQLDB 支持 TEMP 表和三种类型的持久表（MEMORY 表, CACHED 表，TEXT表）
当使用 CREATE TABLE 命令时，Memory 表时默认类型，它们的数据整体保存在内存当中，但是任何改变它们的结构或者内容，它们会被写到
.script 文件中。这个脚本文件在数据库下一次打开的时候被对出，内存表重新被创建内容，根temp 表不同，内存表时持久化的。
CACHED 表通过CREATE CACHED TABLE 命令建立. 只有部分的它们的数据或者索引被保存在内存中，允许大表占用几百兆的内存空间。例外一个优点，在数据库引擎中，启动大量数据的缓存表需要花费少量的时间，缺点是减慢了运行和使用Hsqldb 的速度。表相对小的时候，不要使用cache 表，在小表中使用内存数据库。
从版本 1.7.0 以后，支持text 表，使用 CSV (Comma Separated Value) 或者其它分隔符文本文件作为它们的数据源。你可以特殊指定一个存在的CSV 文件，例如从其它的数据或者程序中导出文件，作为TXT 表的数据源。 同时,你可以指定一个空文件，通过数据库引擎填充数据。TEXT 表将比cache 表更加效率高。Text 表可以指向不同的数据文件。
* memory-only databases 数据库只支持memory 表和cache 表，不支持text 表。
2.8. 约束和索引
HSQLDB 支持 PRIMARY KEY, NOT NULL, UNIQUE, CHECK and FOREIGN KEY 约束.
3. sql 命令
3.1. sql 支持
select top 1 * from test;
select limit 0 2 * from test;
DROP TABLE test IF EXISTS;
3.2. Constraints and Indexes
主健约束：PRIMARY KEY
唯一约束：
唯一索引：
外健：
CREATE TABLE child(c1 INTEGER, c2 VARCHAR, FOREIGN KEY (c1, c2) REFERENCES parent(p1, p2));
3.3. 索引和查询速度
索引提高查询速度，比提高排序速度。
主健和唯一所列自动创建索引，否则需要自己创建CREATE INDEX command。
索引： 唯一索引和非唯一索引
多列的索引，如果只是使用后面的，不使用第一个，将不会条查询速度。
(TB is a very large table with only a few rows where TB.COL3 = 4)
SELECT * FROM TA JOIN TB ON TA.COL1 = TB.COL2 AND TB.COL3 = 4;
SELECT * FROM TB JOIN TA ON TA.COL1 = TB.COL2 AND TB.COL3 = 4;(faster)
原因是 TB.COL3 可以被快速的估计,如果TB 表放到前面(index on TB.COL3):
一般规则是把缩小条件的列的表放在前面
3.4. 使用where 还是join
使用 WHERE 条件链接表可能会降低运行速度.
下面的例子将会比较慢,即使使用了索引:
SELECT ... FROM TA, TB, TC WHERE TC.COL3 = TA.COL1 AND TC.COL3=TB.COL2 AND TC.COL4 = 1
这个查询隐含TA.COL1 = TB.COL2 ,但是没有直接设定这个条件.如果 TA 和 TB 每个表都包含100 条记录,10000 组合将和 TC 关联,用于TC这个列的条件,尽管有索引在这个列上.使用JOIN 关键字, 在组合TC 之前,TA.COL1 = TB.COL2 条件直接并缩小组合 TA 和 TB 的行数, 在运行大数据量的表的结果是,将会很快:
SELECT ... FROM TA JOIN TB ON TA.COL1 = TB.COL2 JOIN TC ON TB.COL2 = TC.COL3 WHERE TC.COL4 = 1
这个查询可以提高一大步,如果改变表的顺序, 所以 TC.COL1 = 1 将最先使用,这样更小的集合将组合在一起:
SELECT ... FROM TC JOIN TB ON TC.COL3 = TB.COL2 JOIN TA ON TC.COL3 = TA.COL1 WHERE TC.COL4 = 1
以上例子,数据引擎自动应用于TC.COL4 = 1 组合小的集合于其它表关联. Indexes TC.COL4, TB.COL2 TA.COL1 都将使用索引,提高查询速度.
3.5. Subqueries and Joins
使用join 和调整表的顺序提高效率.
例如:, 第二个查询的速度将更快一些(TA.COL1 和TB.COL3都有索引):
Example 2.2. Query comparison
SELECT ... FROM TA WHERE TA.COL1 = (SELECT MAX(TB.COL2) FROM TB WHERE TB.COL3 = 4)
SELECT ... FROM (SELECT MAX(TB.COL2) C1 FROM TB WHERE TB.COL3 = 4) T2 JOIN TA ON TA.COL1 = T2.C1
第二个查询将 MAX(TB.COL2) 与一个单记录表相关联. 并使用TA.COL1索引,这将变得非常快. 第一个查询是将 TA 表中的每一条记录不断地与MAX(TB.COL2)匹配.
3.6. 数据类型
TINYINT, SMALLINT, INTEGER, BIGINT, NUMERIC and DECIMAL (without a decimal point) are supported integral types and map to byte, short, int, long and BigDecimal in Java.
Integral Types:
TINYINT, SMALLINT, INTEGER, BIGINT, NUMERIC and DECIMAL
Other Numeric Types:
REAL, FLOAT or DOUBLE
Bit and Boolean Types:
BOOLEAN: UNDEFINED,TRUE,FALSE
NULL values are treated as undefined.
Storage and Handling of Java Objects
Sequences and Identity
Identity Auto-Increment Columns:
The next IDENTITY value to be used can be set with the
ALTER TABLE ALTER COLUMN
RESTART WITH
;
Sequences:
SELECT NEXT VALUE FOR mysequence, col1, col2 FROM mytable WHERE ...
3.7. 事务问题:
SET PROPERTY "sql.tx_no_multi_rewrite" TRUE
4. Connections
通用驱动jdbc:hsqldb: 下列协议标识(mem: file: res: hsql: http: hsqls: https:)
Table 4.1. Hsqldb URL Components
Driver and Protocol Host and Port Database
jdbc:hsqldb:mem:
not available accounts
jdbc:hsqldb:mem:.
jdbc:hsqldb:file:
not available mydb
/opt/db/accounts
C:/data/mydb
数据库路径.
jdbc:hsqldb:res:
not available /adirectory/dbname
jars files are accessed in Java programs. The /adirectory above stands for a directory in one of the jars.
jdbc:hsqldb:hsql:
jdbc:hsqldb:hsqls:
jdbc:hsqldb:http:
jdbc:hsqldb:https:
//localhost
//192.0.0.10:9500
//dbserver.somedomain.com
/an_alias
/enrollments
/quickdb
别名在server.properties or webserver.properties文件中指定
database.0=file:/opt/db/accounts
dbname.0=an_alias
database.1=file:/opt/db/mydb
dbname.1=enrollments
database.2=mem:adatabase
dbname.2=quickdb
In the example below, the database files lists.* in the /home/dbmaster/ directory are associated with the empty alias:
database.3=/home/dbmaster/lists
dbname.3=
4.1.Connection properties
Connection properties are specified either by establishing the connection via the:
DriverManager.getConnection (String url, Properties info);
method call, or the property can be appended to the full Connection URL.
Table 4.2. Connection Properties
get_column_name true column name in ResultSet
This property is used for compatibility with other JDBC driver implementations. When true (the default), ResultSet.getColumnName(int c) returns the underlying column name
When false, the above method returns the same value as ResultSet.getColumnLabel(int column) Example below:
jdbc:hsqldb:hsql://localhost/enrollments;get_column_name=false
When a ResultSet is used inside a user-defined stored procedure, the default, true, is always used for this property.
ifexists false connect only if database already exists
Has an effect only with mem: and file: database. When true, will not create a new database if one does not already exist for the URL.
When false (the default), a new mem: or file: database will be created if it does not exist.
Setting the property to true is useful when troubleshooting as no database is created if the URL is malformed. Example below:
jdbc:hsqldb:file:enrollments;ifexists=true
shutdown false shut down the database when the last connection is closed
This mimics the behaviour of 1.7.1 and older versions. When the last connection to a database is closed, the database is automatically shut down. The property takes effect only when the first connection is made to the database. This means the connection that opens the database. It has no effect if used with subsequent, simultaneous connections.
This command has two uses. One is for test suites, where connections to the database are made from one JVM context, immediately followed by another context. The other use is for applications where it is not easy to configure the environment to shutdown the database. Examples reported by users include web application servers, where the closing of the last connection conisides with the web app being shut down.
4.2. Properties Files
大小写敏感 (e.g. server.silent=FALSE will have no effect, but server.silent=false will work).
属性文件和设定存储如下 :
Table 4.3. Hsqldb Server Properties Files
File Name Location Function
server.properties the directory where the command to run the Server class is issued settings for running HSQLDB as a database server communicating with the HSQL protocol
webserver.properties the directory where the command to run the WebServer class is issued settings for running HSQLDB as a database server communicating with the HTTP protocol
.properties the directory where all the files for a database are located settings for each particular database
Properties files for running the servers are not created automatically. You should create your own files that contain server.property=value pairs for each property.
4.2.1. Server and Web Server Properties
server.properties and webserver.properties 文件支持如下设定:
Table 4.4. Property File Properties
Value Default Description
server.database.0 test the path and file name of the first database file to use
server.dbname.0 "" lowercase server alias for the first database file
server.urlid.0 NONE SqlTool urlid used by UNIX init script. (This property is not used if your are running Server/Webserver on a platform other than UNIX, or of you are not using our UNIX init script).
server.silent true no extensive messages displayed on console
server.trace false JDBC trace messages displayed on console
In 1.8.0, 每个服务器支持同时启动10个不同的数据库. The server.database.0 property defines the filename / path whereas the server.dbname.0 defines the lowercase alias used by clients to connect to that database. The digit 0 is incremented for the second database and so on. Values for the server.database.{0-9} property can use the mem:, file: or res: prefixes and properties as discussed above under CONNECTIONS. For example,
database.0=mem:temp;sql.enforce_strict_size=true;
Values specific to server.properties are:
Table 4.5. Server Property File Properties
Value Default Description
server.port 9001 TCP/IP port used for talking to clients. All databases are served on the same port.
server.no_system_exit true no System.exit() call when the database is closed
Values specific to webserver.properties are:
Table 4.6. WebServer Property File Properties
Value Default Description
server.port 80 TCP/IP port used for talking to clients
server.default_page index.html the default web page for server
server.root ./ the location of served pages
.
? multiple entries such as .html=text/html define the mime types of the static files served by the web server. See the source for WebServer.java for a list.
All the above values can be specified on the command line to start the server by omitting the server. prefix.
5. SqlTool
Mem 数据库:
E:\hsqldb>java -jar ./lib/hsqldb.jar mem
Hsql Server:
(前提是xdb server 已经启动):
(java -cp ../lib/hsqldb.jar org.hsqldb.Server -database.0 file:mydb -dbname.0 xdb)
java -jar ./hsqldb.jar xdb
执行sql 语句:
1)
Mydb.sql :
CREATE MEMORY TABLE TEST(ID INTEGER,NAME VARCHAR(20));
INSERT INTO TEST VALUES(1,'aaa');
INSERT INTO TEST VALUES(2,'bbb');
E:\hsqldb>java -jar ./lib/hsqldb.jar mem mydb.sql
1 row updated
1 row updated
2)
testuser.sql:
CREATE MEMORY TABLE userTEST(ID INTEGER,NAME VARCHAR(20));
INSERT INTO userTEST VALUES(1,'aaa');
INSERT INTO userTEST VALUES(2,'bbb');
commit; //这样才能提交到数据库
E:\hsqldb>java -jar ./hsqldb.jar xdb testuser.sql > file.txt 2>&1
输出结果到file.txt 文件中.
连接oracle:
E:\hsqldb>java -classpath ./classes12.zip;./hsqldb.jar org.hsqldb.util.SqlTool --driver oracle.jdbc.driver.OracleDriver
orcl
sqltool.rc 文件:
urlid orcl
url jdbc:oracle:thin:@localhost:1521:livedoor
username scott
password tiger
driver oracle.jdbc.OracleDriver
以上driver 在一处写出即可,也可以连接别的数据库
连接mysql
E:\hsqldb>java -classpath ./lib/mysql-connector-java-3.1.10-bin.jar;./hsqldb.jar org.hsqldb.util.SqlTool mysqltest
.rc 文件内容:
urlid mysqltest
url jdbc:mysql://localhost:3306/test
username root
password root
driver com.mysql.jdbc.Driver
6. sql 语法
6.1.1. ALTER INDEX[1]
ALTER INDEX
RENAME TO
;
6.1.2. ALTER SEQUENCE[1]
ALTER SEQUENCE
RESTART WITH
;
6.1.3. ALTER SCHEMA[1]
ALTER SCHEMA
RENAME TO
;
6.1.4. ALTER TABLE[1]
ALTER TABLE
ADD [COLUMN]
Datatype
[(columnSize[,precision])] [{DEFAULT
|
GENERATED BY DEFAULT AS IDENTITY (START WITH
[, INCREMENT BY
])}] |
[[NOT] NULL] [IDENTITY] [PRIMARY KEY]
[BEFORE
];
ALTER TABLE
DROP [COLUMN]
;
ALTER TABLE
ALTER COLUMN
RENAME TO
ALTER TABLE
ALTER COLUMN
SET DEFAULT
};
ALTER TABLE
ALTER COLUMN
SET [NOT] NULL
ALTER TABLE
ALTER COLUMN
;
ALTER TABLE
ALTER COLUMN
RESTART WITH
ALTER TABLE
ADD [CONSTRAINT
]
CHECK (
);
ALTER TABLE
ADD [CONSTRAINT
] UNIQUE (
);
ALTER TABLE
ADD [CONSTRAINT
]
PRIMARY KEY (
);
ALTER TABLE
ADD [CONSTRAINT
] FOREIGN KEY (
)
REFERENCES
(
)
[ON {DELETE | UPDATE} {CASCADE | SET DEFAULT | SET NULL}];
ALTER TABLE
DROP CONSTRAINT
;
ALTER TABLE
RENAME TO
;
6.1.5. ALTER USER[1]
ALTER USER
SET PASSWORD
;
ALTER USER
SET INITIAL SCHEMA
;
6.1.6. CALL
CALL Expression;
See also: Stored Procedures / Functions, SQL Expression.
6.1.7. CHECKPOINT
CHECKPOINT [DEFRAG[1]];
See also: SHUTDOWN, SET LOGSIZE.
6.1.8. COMMIT
COMMIT [WORK];
See also: ROLLBACK, SET AUTOCOMMIT, SET LOGSIZE.
6.1.9. CONNECT
CONNECT USER
PASSWORD
;
See also: GRANT, REVOKE.
6.1.10. CREATE ALIAS
CREATE ALIAS
FOR
;
See also: CALL, Stored Procedures / Functions.
6.1.11. CREATE INDEX
CREATE [UNIQUE] INDEX
ON (
[DESC] [, ...]) [DESC];
6.1.12. CREATE ROLE[1]
CREATE ROLE
;
6.1.13. CREATE SCHEMA[1]
CREATE SCHEMA
AUTHORIZATION
[
[
] [...];
CREATE SCHEMA ACCOUNTS AUTHORIZATION DBA
CREATE TABLE AB(A INTEGER, ...)
CREATE TABLE CD(C CHAHR, ...)
CREATE VIEW VI AS SELECT ...
GRANT SELECT TO PUBLIC ON AB
GRANT SELECT TO JOE ON CD;
6.1.14. CREATE SEQUENCE[1]
CREATE SEQUENCE
[AS {INTEGER | BIGINT}]
[START WITH
] [INCREMENT BY
];
SELECT [...,] NEXT VALUE FOR
[, ...] FROM
;
6.1.15. CREATE TABLE
CREATE [MEMORY | CACHED | [GLOBAL] TEMPORARY | TEMP [1] | TEXT[1]] TABLE
(
[, ...] [,
...] )
[ON COMMIT {DELETE | PRESERVE} ROWS];
6.1.16. CREATE TRIGGER[1]
CREATE TRIGGER
{BEFORE | AFTER} {INSERT | UPDATE | DELETE} ON
[FOR EACH ROW] [QUEUE n] [NOWAIT] CALL
;
6.1.17. CREATE USER
CREATE USER
PASSWORD
[ADMIN];
6.1.18. CREATE VIEW[1]
CREATE VIEW
[(
,..) AS SELECT ... FROM ... [WHERE Expression]
[ORDER BY orderExpression [, ...]]
[LIMIT
[OFFSET
]];
CREATE VIEW mealsjv AS
SELECT m.mid mid, m.name name, t.mealtype mt, a.aid aid,
a.gname + ' ' + a.sname author, m.description description,
m.asof asof
FROM meals m, mealtypes t, authors a
WHERE m.mealtype = t.mealtype
AND m.aid = a.aid;
CREATE VIEW mealswebv AS SELECT name, author FROM mealsjv;
CREATE VIEW aview (new_name, new_author) AS
SELECT name, author
FROM mealsjv
6.1.19. DELETE
DELETE FROM table [WHERE Expression];
6.1.20. DISCONNECT
DISCONNECT;
6.1.21. DROP INDEX
DROP INDEX index [IF EXISTS];
6.1.22. DROP ROLE[1]
DROP ROLE
;
6.1.23. DROP SEQUENCE[1]
DROP SEQUENCE
[IF EXISTS] [RESTRICT | CASCADE];
6.1.24. DROP SCHEMA[1]
DROP SCHEMA
[RESTRICT | CASCADE];
6.1.25. DROP TABLE
DROP TABLE [IF EXISTS] [RESTRICT | CASCADE];
6.1.26. DROP TRIGGER
DROP TRIGGER
;
6.1.27. DROP USER
DROP USER
;
6.1.28. DROP VIEW[1]
DROP VIEW
[IF EXISTS] [RESTRICT | CASCADE];
6.1.29. EXPLAIN PLAN
EXPLAIN PLAN FOR { SELECT ... | DELETE ... | INSERT ... | UPDATE ..};
6.1.30. GRANT
GRANT { SELECT | DELETE | INSERT | UPDATE | ALL } [,...]
ON { table | CLASS "package.class" } TO
;
GRANT
[,...] TO
[1];
GRANT SELECT ON Test TO GUEST;
GRANT ALL ON CLASS "java.lang.Math.abs" TO PUBLIC;
6.1.31. INSERT
INSERT INTO table [( column [,...] )]
{ VALUES(Expression [,...]) | SelectStatement};
6.1.32. REVOKE
REVOKE { SELECT | DELETE | INSERT | UPDATE | ALL } [,...]
ON { table | CLASS "package.class" } FROM
;
REVOKE
[,...] FROM
[1];
6.1.33. ROLLBACK
ROLLBACK [TO SAVEPOINT
[1] | WORK}];
6.1.34. SAVEPOINT[1]
SAVEPOINT
;
6.1.35. SCRIPT
SCRIPT ['file'];
6.1.36. SELECT[1]
SELECT [{LIMIT
| TOP
}[1]][ALL | DISTINCT]
{ selectExpression | table.* | * } [, ...]
[INTO [CACHED | TEMP | TEXT][1] newTable]
FROM tableList
[WHERE Expression]
[GROUP BY Expression [, ...]]
[HAVING Expression]
[{ UNION [ALL | DISTINCT] | {MINUS [DISTINCT] | EXCEPT [DISTINCT] } |
INTERSECT [DISTINCT] } selectStatement]
[ORDER BY orderExpression [, ...]]
[LIMIT
[OFFSET
]];
tableList
table [{CROSS | INNER | LEFT OUTER | RIGHT OUTER}
JOIN table ON Expression] [, ...]
table
{ (selectStatement) [AS] label | tableName}
selectExpression
{ Expression | COUNT(*) | {
COUNT | MIN | MAX | SUM | AVG | SOME | EVERY |
VAR_POP | VAR_SAMP | STDDEV_POP | STDDEV_SAMP
} ([ALL | DISTINCT][1]] Expression) } [[AS] label]
If CROSS JOIN is specified no ON expression is allowed for the join.
orderExpression
{ columnNr | columnAlias | selectExpression }
[ASC | DESC]
LIMIT n m
LIMIT n m
LIMIT m OFFSET n
TOP m
UNION and other set operations
6.1.37. SET AUTOCOMMIT
SET AUTOCOMMIT { TRUE | FALSE };
6.1.38. SET DATABASE COLLATION[1]
SET DATABASE COLLATION
;
6.1.39. SET CHECKPOINT DEFRAG[1]
SET CHECKPOINT DEFRAG
;
6.1.40. SET IGNORECASE
SET IGNORECASE { TRUE | FALSE };
6.1.41. SET INITIAL SCHEMA [1]
Users may change their base default schema name with the comand
SET INITIAL SCHEMA
;
6.1.42. SET LOGSIZE
SET LOGSIZE
;
6.1.43. SET PASSWORD
SET PASSWORD
;
6.1.44. SET PROPERTY[1]
SET PROPERTY
;
6.1.45. SET REFERENTIAL INTEGRITY
SET REFERENTIAL_INTEGRITY { TRUE | FALSE };
6.1.46. SET SCHEMA[1]
SET SCHEMA
;
6.1.47. SET SCRIPTFORMAT[1]
SET SCRIPTFORMAT {TEXT | BINARY | COMPRESSED};
6.1.48. SET TABLE INDEX
SET TABLE tableName INDEX 'index1rootPos index2rootPos ... ';
6.1.49. SET TABLE READONLY[1]
SET TABLE
READONLY {TRUE | FALSE};
6.1.50. SET TABLE SOURCE[1]
SET TABLE
SOURCE
[DESC];
SET TABLE mytable SOURCE "myfile;fs=|;vs=.;lvs=~"
Supported Properties
quoted = { true | false }
default is true. If false, treats double quotes as normal characters
all_quoted = { true | false }
default is false. If true, adds double quotes around all fields.
encoding =
character encoding for text and character fields, for example, encoding=UTF-8
ignore_first = { true | false }
default is false. If true ignores the first line of the file
cache_scale=
exponent to calculate rows of the text file in cache. Default is 8, equivalent to nearly 800 rows
cache_size_scale =
r
exponent to calculate average size of each row in cache. Default is 8, equivalent to 256 bytes per row.
fs =
field separator
vs =
varchar separator
lvs =
long varchar separator
Special indicators for Hsqldb Text Table separators
\semi
semicolon
\quote
quote
\space
space character
\apos
apostrophe
\n
newline - Used as an end anchor (like $ in regular expressions)
\r
carriage return
\t
tab
\\
backslash
\u####
a Unicode character specified in hexadecimal
Only an administrator may do this.
6.1.51. SET WRITE DELAY[1]
SET WRITE_DELAY {{ TRUE | FALSE } |
|
MILLIS};
6.1.52. SHUTDOWN
SHUTDOWN [IMMEDIATELY | COMPACT | SCRIPT[1]];
6.2. Data Types
Table 9.1. Data Types. The types on the same line are equivalent.
Name Range Java Type
INTEGER | INT as Java type int | java.lang.Integer
DOUBLE [PRECISION] | FLOAT as Java type double | java.lang.Double
VARCHAR as Integer.MAXVALUE java.lang.String
VARCHAR_IGNORECASE as Integer.MAXVALUE java.lang.String
CHAR | CHARACTER as Integer.MAXVALUE java.lang.String
LONGVARCHAR as Integer.MAXVALUE java.lang.String
DATE as Java type java.sql.Date
TIME as Java type java.sql.Time
TIMESTAMP | DATETIME as Java type java.sql.Timestamp
DECIMAL No limit java.math.BigDecimal
NUMERIC No limit java.math.BigDecimal
BOOLEAN | BIT as Java type boolean | java.lang.Boolean
TINYINT as Java type byte | java.lang.Byte
SMALLINT as Java type short | java.lang.Short
BIGINT as Java type long | java.lang.Long
REAL as Java type double | java.lang.Double[1]
BINARY as Integer.MAXVALUE byte[]
VARBINARY as Integer.MAXVALUE byte[]
LONGVARBINARY as Integer.MAXVALUE byte[]
OTHER | OBJECT as Integer.MAXVALUE java.lang.Object
The uppercase names are the data types names defined by the SQL standard or commonly used by RDMS's. The data types in quotes are the Ja
6.2.1. 自动增长:
create table user(id IDENTITY,name varchar(20));
sql> create table dept(id int GENERATED BY DEFAULT AS IDENTITY(start with 10,increment by 5) not null PRIMARY KEY,name v
archar(20));
sql> insert into dept(name) values('asc');
1 row updated
sql> insert into dept(name) values('security');
1 row updated
sql> select * from dept;
ID NAME
-- --------
10 asc
15 security
2 rows
6.3. SQL Comments
-- SQL style line comment
// Java style line comment
/* C style line comment */
7. Hsqldb Test Utility
拷贝 junit.jar 到/lib 目录下
运行: ant hsqldbtest
生成 hsqldbtest.jar
运行: \hsqldb\testrun\hsqldb>runtest TestSelf