Install Oracle 11g R2 on Ubuntu

Ubuntu is not an official supported linux version from Oracle, so I still get some errors during the install process even with required configuration, anyway, it can work and what i'm doing here is try to setup an experiment environment, it's enough to me, any one who want to deploy Oracle in product mode should have supported linux platform like RedHat, OK, following is the steps i have to install it:

1. If you were in multihomed enviroment, set the ORACLE_HOSTNAME variable:
    export ORACLE_HOSTNAME=machine_name.domain_name

2. Create create OSDBA (dba) group, Oracle Inventory group (oinstall)  and a user "oracle" which has "dba" as its login group and oinstall as its 2nd group.

3. Modify /etc/sysctl.conf, set kernel parameter:

4. Modify /etc/security/limits.conf to improve the "number of process" and "number of open file"  performance for oracle:

5. Modify /etc/pam.d/login, add:

6. Modify /etc/profile:

7. Change user to oracle if you haven't done it yet

8. Create base directory, for me it's "/app/oracle"

9. Export ORACLE_BASE, ORACLE_SID

10.  If you're trying to install oracle with a X window:

11. run installer:

12. Oracle should start, if the installer GUI cannot be start, check the error messages, most time it's because a wrong X window configuration, if you are running X window with Xming, just like me, please do make sure to check the "No Access Control" check box in the launch, otherwise, Xming will reject the connection.

13. Now the GUI shoudl open, like what you did in the Windows system, fullfill required value and click next, ingore all errors if there is any condition that is not match, click finish in the last step, it should start install process.

14. After install oracle, the installer GUI will ask you to run two .sh files, run it with a root role.

15. You can try to visit https://you.ip.address:1158/em to see is that OK for you.

16. How to start oracle:


Reference
http://download.oracle.com/docs/cd/B19306_01/install.102/b15660/pre_install.htm#BABDFJAE

posted @ 2010-03-16 15:57 Find it, try it, experience it 阅读(587) | 评论 (0) | 编辑 收藏

How to connect Reliance Modem AC2726 on Linux Ubuntu 9.10

1. Type command: lsusb
2. Install "usb-modeswitch", then re-plugin modem again and input command "lsusb" again, you should get the following output
3. Notice in step #2, the product code has been changed from "fff5" to "fff1".
4. Install package "wvdial" which is used to dail up
5. Type command: "sudo modprobe usbserial vendor=0x19d2 product=0xfff1", don't forget the "sudo"
6. Type command: "sudo wvdialconf", again don't forget the "sudo", this will detect your modem
7. Modify file "/etc/wvdial.conf", following is what I have:

8. Repeat step #5 again and then if you with not bad luck type in command "sudo wvdial", you should connect in.
9. If bad luck with you, click right-upper corner, there is a connection configuration menu, you can create "Mobile Broadband" connection yourself here, don't forget input the phone number "#777" (for China Telcom) and your username password, after that click connect, this works for me.
10. Good luck with you.
11. BTW, if it still cannot work, try to re-plug in the modem.

posted @ 2010-03-12 18:03 Find it, try it, experience it 阅读(390) | 评论 (0) | 编辑 收藏

Oracle Tips Part Two

1. It will not get data from DB when just open the cursor, data will be loaded as an ongoing basis.

2. SCN: System Change Number/System Commit Number

3. FLASH BACK AS OF SCN;

4. You can also flash back table: FLASHBACK TABLE SOME_TABLE TO SCN :SCN_NUM;

5. But before you do a flash back operation on a table, do make sure you have already enbale ROW MOVEMENT on that table.

posted @ 2010-03-07 18:03 Find it, try it, experience it 阅读(172) | 评论 (0) | 编辑 收藏

Oracle Tips One

1. Do use oracle "Bind variable", it can increase the speed by 90 percent in 10g release1.

2. Understand how to use "lock", read never block write,  vice verse.

3. There is a side effect from oracle regarding to the "lock", if you do want to control the access to one row at a specify time (like doing an if 'this row belong to some search condition' then 'modify this row' action), you have to write some logic yourself, for example use the "for update" statement, like: "select * from x where x.id = 1 for update", so that you can lock the row only with id equals to '1' and then modify this row, so that some orther concurrence requests should execute the same sql first, yes, with the same 'for update' statement, and because you already have locked this row(id = 1), orther requests cannot get the access to it, and you get the access control to this row.

4. Regardint to item 3, it will not decrease the concurrence level, because first you only lock the item with id equals to 1 and there maybe thousands of items in your table, second, it will not block the read request.

posted @ 2010-03-06 21:25 Find it, try it, experience it 阅读(222) | 评论 (0) | 编辑 收藏

算法求解!如何判断一个单向链表是否有环路?

这该死的问题让我竟然没有想到解决方案...脑子生锈了？呵呵，算了...

该问题最经典的解答，简直是一句话惊醒梦中人啊

“用两个指针，一个的步长为 1，另外一个的为 2，从表头开始一起往前走，如果相遇，表明有环路，否则就是没有了。”

下来，不用说什么了吧，用JAVA实现的话，声明两个Iterator A 和 B，A 每次调用两个NEXT，B只调用一次，如果他们能够相遇，就是有环...我操

posted @ 2009-03-02 14:15 Find it, try it, experience it 阅读(605) | 评论 (0) | 编辑 收藏

Something you may ingore when to use Hibernate and JPA.

The first is about identity generator, this is something I ingored and find really interesting later when I read back the document.

    When you choose "native" (for plain hibernate) or "AUTO" (for JPA which use hibernate as provider) as identity generator, it (actually they are the same identity generator but with different name in different scope) will pick other identity generators like identity, sequence, or hilo, depending on the capabilities of the underlying database. Use this generator to keep your mapping metadata portable to different database management systems.
    If your underlying DB is oracle, it will automatically create a sequence for you which means choose the sequence as identity generator, that's really interesting, at least for me for the first time when it comes to me.

The second is about the flush and close session operations when to use hibernate with JTA transaction.

    You should manually flush your operation by call flush method and close your session by calling close method when you try to use JTA transaction instead of hibernate Transaction API, these is because hibernate Transaction API does thoes operations automatically for you. But, with following configuration, it can also be done automatically for you by hibernate, though you are still with JTA transaction.

    hibernate.transaction.flush_before_completion=true
    hibernate.transaction.auto_close_session=true

The third is about an interesting code snatch listed as follow:
   
    What happen if you don't commit the transaction? It's depends on the underlying DB, for oracle it will commit any uncommited transactions, but for many other DB vendors, they will roll back any pending transactions.
   

posted @ 2008-04-03 16:32 Find it, try it, experience it 阅读(906) | 评论 (0) | 编辑 收藏