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resolution to "Can't rollforward due to large bufferpool size "

MyJavaWorld — Thu, 15 Mar 2007 07:21:00 GMT

Question:
The restore command works fine, but while attempting the rolforward of the sql logs, it complains about database falling short on bufferpool,and then terminates the rollforward process. One close look at the db2diag.log file, I noticed that db2 tried to start the database with the hidden bufferpool. But, apparently, that hidden bufferpool was pretty small to rollforward the logs and bring it online.

I cannot reduce the bufferpool size as the database cannot be connected to.I cannot connect to the database as it is in rollforward pending state. I cannot rollforward the database, as it's not happy with the size of the *hidden* bufferpool and terminates.

Answer:

db2set DB2_OVERRIDE_BPF=50000

This will bring up all configured bufferpools using 50000 pages each. You
can choose a smaller/larger value that is suitable for your number of
bufferpools and available system memory. You can also configure each
bufferpool individually if you want

�? 正数のペヹ{��?
OR
[;...] (=<バッファヹ{��プー�?ID>,<ページ数> )

There is sitiuation that above solution does not work.

				When you try to create a bufferpool or alter a bufferpool to a
very large size and there is not enough memory in the system
, DB2 may occupies all pagespace and overrall performance of
the system become slow and may get hang at last because no
pagespace is available. Then after you connect the database
next time, DB2 will do crash recovery and still try to
allocate memory for this big bufferpool and occupy all
pagespace again. when you specify DB2_OVERRIDE_BPF parameter
to override bufferpool size, it doesn't take effect in this
situation. This is becasue DB2_OVERRIDE_BPF only applies for
bufferpools that already exist at startup, and not to
bufferpools that are created during crash recovery or roll
forward. We will fix this problem and check DB2_OVERRIDE_BPF
registry when creating bufferpools during crash recovery or
roll forward. This problem only occurs in a 64 bit instance.

Local fix

				You can use db2iupdt -w 32  to update the instance to
a 32 bit instance, then you can connect to the database
succefully. After that, use db2iupdt -w 64  to update
the instance to 64 bit again. Please take a backup at this
point, so we don't have to roll forward through bufferpool
creation that fails if we need restore and roll forward
database.

Problem summary

				Users Affected:
All users using 64 bit instance
Problem Description:
When you try to create a bufferpool or alter a bufferpool to a
very large size and there is not enough memory in the system
, DB2 may occupies all pagespace and overrall performance
of the system become slow and may get hang at last
because no pagespace is available. Then after you connect the
database at next time, DB2 will do crash recovery and still try
to allocate
memory for this big bufferpool and occupy all pagespace again.
In this situation, when you specify DB2_OVERRIDE_BPF parameter
to override bufferpool size, it doesn't take effect in this
situation. This
is becasue DB2_OVERRIDE_BPF only applies for bufferpools that
already exist at startup, and not to bufferpools that are
created during crash recovery or roll forward. We will fix
this problem and check
DB2_OVERRIDE_BPF registry when creating bufferpools during crash
recovery or roll forward. This problem only occurs in 64 bit
instance.
Problem Summary:
This problem is caused by a misoperation, when you create or alt
er a bufferpool, the size is too large to allocated from OS and
cause overrall performance of the system is very slow and seems
hang. Another problem is that DB2_OVERRIDE_BPF registry only app
lies to bufferpools that already exists, and not bufferpools wil
l be created in crash recovery or roll forward. So DB2 will try
to create this big bufferpool again when doing crash recovery or
 roll forward. We will fix this problem and check DB2_OVERRIDE_B
PF registry in our crash recovery and roll forward code.

Problem conclusion

Temporary fix

				You can use db2iupdt -w 32  to update the instance to
a 32 bit instance, then you can connect to the database
succefully. After that, use db2iupdt -w 64  to update
the instance to 64 bit again. Please take a backup at this
point, so we don't have to roll forward through bufferpool
creation that fails if we need restore and roll
forward database.Please also notice that be careful when creati
ng bufferpool, don't specify a too large value.

MyJavaWorld 2007-03-15 15:21 发表评论

about DB2 Administration (refer from others)

MyJavaWorld — Thu, 15 Mar 2007 07:00:00 GMT

Change db2 password in db2 level

December 28, 2006

DB2 depends on operation system level authorization to control DB2 system access.

In some case, our db2 account only allows to connect to instance or database, but not log on the system. In other words, we are not able to use the account to get a shell on unix or logon locally on windows.

As usual, when we need to change db2 password, we take action on the system level because it's more frank. But in the case above that we can't get logon, we have to do it on db2 level. There are 2 ways.

Use the GUI tool DB2 Configuration Assistance
Use the command line tools DB2 CLP or CE

Using DB2 Configuration Assistance

Right click on a database name, then choose "Change password".

Note: When more than one databases live in same system, we might share the same account in multi-database. Changing password for one of them will affect all databases in this system. In other words, we don't need to do the change on each database, we could choose any we have privileges on the system.

Limitation: We are not able to change our password in the case of that we are only allowed to attach to the node but not connect to any database, or we don't get the catalog information for any database in the node.

For this limitation, it works out with the 2nd way.

Using DB2 CLP and CE

We could use CLP and CE to change password for databases and nodes that we connected or attached to.

Change by connecting to database

C:\> db2 connect to SAMPLE user TEST using OLDPWD new NEWPWD confirm NEWPWD
C:\> db2 connect to SAMPLE user TEST using OLDPWD change password

Change by attaching to node, this way works out for the limitation in Configuration Assistance

C:\> db2 attach to NODE user TEST using OLDPWD new NEWPWD confirm NEWPWD
C:\> db2 attach to NODE user TEST using OLDPWD change password

标签 Tags: 其它�?a >DB2 (13), Password (1) 相关的话�?/p>

Posted by Alex at 2:16 PM | Comments (0) | TrackBack (0) | Edit

alter table xxx VOLATILE

April 27, 2006

valatile

a. 反复无常�?挥发性的

VOLATILE CARDINALITY or NOT VOLATILE CARDINALITY
Indicates to the optimizer whether or not the cardinality of table table-name can
vary significantly at run time. Volatility applies to the number of rows in the
table, not to the table itself. CARDINALITY is an optional keyword. The default
is NOT VOLATILE.

VOLATILE
Specifies that the cardinality of table table-name can vary significantly at
run time, from empty to large. To access the table, the optimizer will use
an index scan (rather than a table scan, regardless of the statistics) if that
index is index-only (all referenced columns are in the index), or that index
is able to apply a predicate in the index scan. The list prefetch access method
will not be used to access the table. If the table is a typed table, this option
is only supported on the root table of the typed table hierarchy (SQLSTATE 428DR).

NOT VOLATILE
Specifies that the cardinality of table-name is not volatile.
Access plans to this table will continue to be based on existing statistics and
on the current optimization level.

NOTE: The keyword could be specified within ALTER TABLE, but not CREATE TABLE.

标签 Tags: 其它�?a >DB2 Administration (12) 相关的话�?/p>

Posted by Alex at 2:20 PM | Comments (0) | TrackBack (0) | Edit

Difference between Local and System Database Directory

April 13, 2006

DB2 automatically catalogs databases when they are created. It catalogs an entry
for the database in the local database directory and another entry in the system
database directory. If the database is created from a remote client (or a client which
is executing from a different instance on the same machine), an entry is also made
in the system database directory at the client instance.

Databases on the same node as the database manager instance are cataloged as
indirect entries. Databases on other nodes are cataloged as remote entries.

List DBs in Local Database Directory

$ db2 list db directory on /path_to_where_db_created

List DBs in System Database Directory

$ db2 list db directory

标签 Tags: 其它�?a >DB2 Administration (12) 相关的话�?/p>

Posted by Alex at 2:55 PM | Comments (0) | TrackBack (0) | Edit

Illustration of standard tables

April 12, 2006

标签 Tags: 其它�?a >DB2 Administration (12) 相关的话�?/p>

Posted by Alex at 6:26 PM | Comments (0) | TrackBack (0) | Edit

Query the status for one specified tablespace?

April 12, 2006

As we know, we could issue following command to query status for all of tablespaces in current connected DB.

$ db2 list tablespaces show detail > /tmp/ts.list

Then find the status for the tablespaces we concerned.

Is there's a way to query the status for one specified tablespace?

My answer is No.

First, I don't find the related column defination in the table or view:
- sysibm.systablespaces
- syscat.tablespaces
Second, I don't think DB2 stores the status flag within syscata tables. The reason is that once a tablespace comes into a special status, it will not be allowed changing any longer(this may also happen on a system catalog tablespace.) that will lead to a conflict on changing the tablespace status flag if stores it within system catalog tables.

标签 Tags: 其它�?a >DB2 Administration (12), tablespace status (1) 相关的话�?/p>

Posted by Alex at 5:09 PM | Comments (0) | TrackBack (0) | Edit

Illustration of the DMS table-space address map

April 11, 2006

标签 Tags: 其它�?a >DB2 Administration (12) 相关的话�?/p>

Posted by Alex at 4:46 PM | Comments (0) | TrackBack (0) | Edit

DB2 directories and files

April 11, 2006

http://publib.boulder.ibm.com/infocenter/db2luw/v8//topic/com.ibm.db2.udb.doc/admin/c0005420.htm

标签 Tags: 其它�?a >DB2 Administration (12) 相关的话�?/p>

Posted by Alex at 3:51 PM | Comments (0) | TrackBack (0) | Edit

Illustration of DB2 architechure and process

April 11, 2006

Reference

http://publib.boulder.ibm.com/infocenter/db2luw/v8//topic/com.ibm.db2.udb.doc/admin/c0005418.htm

标签 Tags: 其它�?a >DB2 Administration (12) 相关的话�?/p>

Posted by Alex at 2:21 PM | Comments (0) | TrackBack (0) | Edit

Tablespaces are put into backup pending after a load

March 29, 2006

DB2 sets tablespace as Backup Pending state after loading data into a table in linear logging database(that is, logretain or userexit is on), whatever the load is successful or failed. the reason is that the load process will not write log file. from the begin time of loading to the end time of loading, there will be a blank segment in log file, and the rollforward recovery can Not jump over the blank segment to apply the later log file.

so database needs a backup after loading to make sure db2 have recovery capicibility.

it's able to use ~~[COPY YES|NO] or~~ [NONRECOVERABLE] to prevent tablespace go into Backup Pending state. ~~COPY YES will do the backup automatically after loading, and COPY NO and~~ NONRECOVERABLE will give up this backup that means db2 will be not able to recover the database once an serious error occured.

�l�箋阅读 "Tablespaces are put into backup pending after a load" 的剩余内�?/p>

标签 Tags: 其它�?a >DB2 Administration (12), Load (1), Tablespace (1) 相关的话�?/p>

Posted by Alex at 5:31 PM | Comments (0) | TrackBack (0) | Edit

Come pending when droping Procedures

March 21, 2006

Problem Description

There's no any response for creating or droping any procedures in DB2. Seems it's pending there, without any error returned. This time UPDATE statement on tables could be issued successfully.

Check Process

Check OS disk available

$ df -kl

Check database configure

db2 => get db cfg |more

Check system catalog tablespace

db2 => list tablespaces show detail |more
syscatspace	0x0000

Cause

It caused by issuing CREATE or DROP statement without COMMIT or ROLLBACK statement in CLP which is in non-Autocommit mode.

Solution

After you issue a COMMIT or a ROLLBACK in the CLP or close it, the pending is gone.

We must be very careful when we use client in non-Autocommit mode just like CLPs in this case.

To check the Autocommit mode in CLP issues. Refer to:

set COMMIT mode in db2 clp

db2 => list command options

 -c    自动落实                                  OFF

From this point, we could get more. Most of strange things like this(pending there and no error return) are caused by locking.

In this case, it was only the opertation on procedures being pended, so track on this thread to suppose the syscat tables related with procedures are locked then find the what probably causes it.

标签 Tags: 其它�?a >DB2 Administration (12), DB2 Development (24), Procedure (3) 相关的话�?/p>

Posted by Alex at 6:13 PM | Comments (0) | TrackBack (0) | Edit

db2 can not create index on local view

March 7, 2006

There's an object called index view since MS SQL Server 2000, it's an index which is created on an view which is based on a local table. it is attent to imporve the select performence on the view when this view is based on multi-table and has complex logic.

I try to find a simular thing in DB2, but there's no the simular solution in DB2 v8.2 for now. Instead, I found another thing instested.

DB2 allows creating index on the tables or views in remote data source, such as a database on another host or an XML data source. To be exactly, that's Not true Index, it's Index Specification. It requests that the tables in remote data source have created index in its own system. And it only repeat the index description in local system.

										Local DB2 Env                                            Remote DB2 Env
										

										
Index Specification    ->    Nickname    - - ->   True Index    ->    Table

See following example in DB2 info center.

CREATE INDEX statement
http://publib.boulder.ibm.com/infocenter/db2luw/v8//topic/com.ibm.db2.udb.doc/admin/r0000919.htm?resultof=%22%63%72%65%61%74%65%22%20%22%63%72%65%61%74%22%20%22%69%6e%64%65%78%22%20%22%73%74%61%74%65%6d%65%6e%74%22%20

Example 3: The nickname EMPLOYEE references a data source table called CURRENT_EMP. After this nickname was created, an index was defined on CURRENT_EMP. The columns chosen for the index key were WORKDEBT and JOB. Create an index specificationindex. Through this specification, the optimizer will know that the index exists and what its key is. With this information, the optimizer can improve its strategy to access the table. that describes this

   CREATE UNIQUE INDEX JOB_BY_DEPT
     ON EMPLOYEE (WORKDEPT, JOB)
     SPECIFICATION ONLY

Note: the Nickname is only allowed to be created on tables in local database and on much kind of objects at remote data source. It's not allowed to be created on views in local database.

标签 Tags: 其它�?a >DB2 Administration (12), index (1) 相关的话�?/p>

Posted by Alex at 5:43 PM | Comments (0) | TrackBack (0) | Edit

set COMMIT mode in db2 clp

February 28, 2006

As default, DB2 CLP will do commit after you issue each DB2 statements or SQL automatically.

If you want to change it instead of issuing COMMIT or ROLLBACK manually, do following.

SQLLIB\BIN> db2
db2 => list command options
    -c   ON
db2 => update command options using c off
db2 => list command options
    -c    OFF

This change will only exists during this session. The setting will lose when you close this CLP and open CLP next time.

following cmd will get the same result with above.

SQLLIB\BIN> db2 list command options
    -c    ON
SQLLIB\BIN> db2 +c
db2 =>
db2 => list command options
    -c    OFF
db2 => quit
SQLLIB\BIN> db2 list command options
    -c    ON

There's also the way to keep the settings forever, do following.

SQLLIB\BIN\> db2 list command options
    -c    ON
SQLLIB\BIN\> db2set db2options=+c
SQLLIB\BIN\> db2 list command options
    -c    OFF

This change will take effection immediately even for others having been opened CLP windows. And will keep along.

Use following cmd set it back to ON.

SQLLIB\BIN> db2set db2opptions=-c

Reference

http://www.chinaunix.net/jh/22/164405.html

标签 Tags: 其它�?a >commit (1), DB2 Administration (12) 相关的话�?/p>

Posted by Alex at 8:28 PM | Comments (0) | TrackBack (0) | Edit

表与索引的重命名 RENAME

August 18, 2005

在DB2 中重命名表或者烦�?/p>

db2=> RENAME TABLE EMP TO EMPLOYEE
db2=> RENAME TABLE ABC.EMP TO EMPLOYEE 
db2=> RENAME INDEX NEW-IND TO IND
db2=> RENAME INDEX ABC.NEW-IND TO IND

MyJavaWorld 2007-03-15 15:00 发表评论

三个UNIX文�g旉��ctime、mtime、atime

MyJavaWorld — Tue, 13 Mar 2007 09:51:00 GMT

三个UNIX文�g旉��ctime、mtime、atime
       我曾�l�根据文件的状态在指定旉��内是否改变写�q�一个WatchDog来对服务�q�行监控�Q�其间曾被这三个旉��搞�؜淆，所以觉得很有必要和大家分��n我对�q�三个术语的理解�?br />      ctime�Q�change time�Q�改变时��_��是指文�g状态最后一�ơ被改变的时��_��
      mtime�Q�modification time�Q�修�Ҏ(gu��)��_��是指文�g内容最后一�ơ被改变的时��_��
      atime�Q�access time�Q�访问时��_��是指文�g最后一�ơ被��d��的时间�?br />      前两者的区别��在于文件状态的改变既包括文件烦引节点的改变�Q�也包括文�g内容的改变。也��是说如果你改变了文件内容，则同时更��C��ctime和mtime�Q�但是如果你只改变了文�g索引节点则只是改变了ctime。atime只有在文件被��d��的时侯才会改变。它的改变与文�g状态以及文件内容的改变没有直接的联�p�R�?br />     例如�Q�echo “Hello World�?>> myfile 则同时改变了ctime和mtime�Q�atime不变�Q?br />     chmod u+x myfile 则只改变了ctime,mtime和atime不变�?br />     cat myfile�Q�则只改变了atime�Q�ctime和mtime不变
     ps:以上操作均在redhat linux下验证通过

MyJavaWorld 2007-03-13 17:51 发表评论

DB2/SQL命��o大全

MyJavaWorld — Thu, 28 Dec 2006 08:57:00 GMT

查看文章

DB2/SQL命��o大全

2006-12-25 13:21

�q�接数据库：

connect to [数据库名] user [操作用户名] using [密码]

创徏�~�冲�?8K)�Q?/p>

  create bufferpool ibmdefault8k IMMEDIATE  SIZE 5000 PAGESIZE 8 K ;
创徏�~�冲�?16K)(OA_DIVERTASKRECORD)�Q?br />  create bufferpool ibmdefault16k IMMEDIATE  SIZE 5000 PAGESIZE 16 K ;
创徏�~�冲�?32K)(OA_TASK)�Q?br />  create bufferpool ibmdefault32k IMMEDIATE  SIZE 5000 PAGESIZE 32 K ;

创徏表空��_��

CREATE TABLESPACE exoatbs IN DATABASE PARTITION GROUP IBMDEFAULTGROUP PAGESIZE 8K MANAGED BY SYSTEM USING ('/home/exoa2/exoacontainer') EXTENTSIZE 32 PREFETCHSIZE 16 BUFFERPOOL IBMDEFAULT8K OVERHEAD 24.10 TRANSFERRATE 0.90 DROPPED TABLE RECOVERY OFF;

CREATE TABLESPACE exoatbs16k IN DATABASE PARTITION GROUP IBMDEFAULTGROUP PAGESIZE 16K MANAGED BY SYSTEM USING ('/home/exoa2/exoacontainer16k' ) EXTENTSIZE 32 PREFETCHSIZE 16 BUFFERPOOL IBMDEFAULT16K OVERHEAD 24.1 TRANSFERRATE 0.90 DROPPED TABLE RECOVERY OFF;

CREATE TABLESPACE exoatbs32k IN DATABASE PARTITION GROUP IBMDEFAULTGROUP PAGESIZE 32K MANAGED BY SYSTEM USING ('/home/exoa2/exoacontainer32k' ) EXTENTSIZE 32 PREFETCHSIZE 16 BUFFERPOOL IBMDEFAULT32K OVERHEAD 24.1 TRANSFERRATE 0.90 DROPPED TABLE RECOVERY OFF;

GRANT USE OF TABLESPACE exoatbs TO PUBLIC;
GRANT USE OF TABLESPACE exoatbs16k TO PUBLIC;
GRANT USE OF TABLESPACE exoatbs32k TO PUBLIC;

创徏�pȝ��表空��_��

CREATE TEMPORARY TABLESPACE exoasystmp IN DATABASE PARTITION GROUP IBMTEMPGROUP PAGESIZE 8K MANAGED BY SYSTEM USING ('/home/exoa2/exoasystmp' ) EXTENTSIZE 32 PREFETCHSIZE 16 BUFFERPOOL IBMDEFAULT8K OVERHEAD 24.10 TRANSFERRATE 0.90 DROPPED TABLE RECOVERY OFF;

CREATE TEMPORARY TABLESPACE exoasystmp16k IN DATABASE PARTITION GROUP IBMTEMPGROUP PAGESIZE 16K MANAGED BY SYSTEM USING ('/home/exoa2/exoasystmp16k' ) EXTENTSIZE 32 PREFETCHSIZE 16 BUFFERPOOL IBMDEFAULT16K OVERHEAD 24.10 TRANSFERRATE 0.90 DROPPED TABLE RECOVERY OFF;

CREATE TEMPORARY TABLESPACE exoasystmp32k IN DATABASE PARTITION GROUP IBMTEMPGROUP PAGESIZE 32K MANAGED BY SYSTEM USING ('/home/exoa2/exoasystmp32k') EXTENTSIZE 32 PREFETCHSIZE 16 BUFFERPOOL IBMDEFAULT32K OVERHEAD 24.10 TRANSFERRATE 0.90 DROPPED TABLE RECOVERY OFF;

1. 启动实例(db2inst1):

db2start

2. 停止实例(db2inst1):

db2stop

3. 列出所有实�?db2inst1)

db2ilist

5.列出当前实例:

db2 get instance

4. 察看�C�Z��配置文�g:

db2 get dbm cfg|more

5. 更新数据库管理器参数信息:

db2 update dbm cfg using para_name para_value

6. 创徏数据�?

db2 create db test

7. 察看数据库配�|�参��C��?/p>

db2 get db cfg for test|more

8. 更新数据库参数配�|�信�?/p>

db2 update db cfg for test using para_name para_value

10.删除数据�?

db2 drop db test

11.�q�接数据�?/p>

db2 connect to test

12.列出所有表�I�间的详�l�信息�?/p>

db2 list tablespaces show detail

13.查询数据:

db2 select * from tb1

14.删除数据:

db2 delete from tb1 where id=1

15.创徏索引:

db2 create index idx1 on tb1(id);

16.创徏视图:

db2 create view view1 as select id from tb1

17.查询视图:

db2 select * from view1

18.节点�~�目

db2 catalog tcp node node_name remote server_ip server server_port

19.察看端口�?/p>

db2 get dbm cfg|grep SVCENAME

20.��试节点的附�?/p>

db2 attach to node_name

21.察看本地节点

db2 list node direcotry

22.节点反编�?/p>

db2 uncatalog node node_name

23.数据库编�?/p>

db2 catalog db db_name as db_alias at node node_name

24.察看数据库的�~�目

db2 list db directory

25.�q�接数据�?/p>

db2 connect to db_alias user user_name using user_password

26.数据库反�~�目

db2 uncatalog db db_alias

27.导出数据

db2 export to myfile of ixf messages msg select * from tb1

28.导入数据

db2 import from myfile of ixf messages msg replace into tb1

29.导出数据库的所有表数据

db2move test export

30.生成数据库的定义

db2look -d db_alias -a -e -m -l -x -f -o db2look.sql

31.创徏数据�?/p>

db2 create db test1

32.生成定义

db2 -tvf db2look.sql

33.导入数据库所有的数据

db2move db_alias import

34.重组��?/p>

db2 reorgchk

35.重组表tb1

db2 reorg table tb1

36.更新�l�计信息

db2 runstats on table tb1

37.备䆾数据库test

db2 backup db test

38.恢复数据库test

db2 restore db test

399\.列出容器的信�?/p>

db2 list tablespace containers for tbs_id show detail

40.创徏�?

db2 ceate table tb1(id integer not null,name char(10))

41.列出所有表

db2 list tables

42.插入数据:

db2 insert into tb1 values(1,’sam�?;

db2 insert into tb2 values(2,’smitty�?;

. 建立数据库DB2_GCB

CREATE DATABASE DB2_GCB ON G: ALIAS DB2_GCB

USING CODESET GBK TERRITORY CN COLLATE USING SYSTEM DFT_EXTENT_SZ 32

2. �q�接数据库�?/p>

connect to sample1 user db2admin using 8301206

3. 建立别名

create alias db2admin.tables for sysstat.tables;

CREATE ALIAS DB2ADMIN.VIEWS FOR SYSCAT.VIEWS

create alias db2admin.columns for syscat.columns;

create alias guest.columns for syscat.columns;

4. 建立表�?/p>

create table zjt_tables as

(select * from tables) definition only;

create table zjt_views as

(select * from views) definition only;

5. 插入记录

insert into zjt_tables select * from tables;

insert into zjt_views select * from views;

6. 建立视图

create view V_zjt_tables as select tabschema,tabname from zjt_tables;

7. 建立触发器�?/p>

CREATE TRIGGER zjt_tables_del

AFTER DELETE ON zjt_tables

REFERENCING OLD AS O

FOR EACH ROW MODE DB2SQL

Insert into zjt_tables1 values(substr(o.tabschema,1,8),substr(o.tabname,1,10))

8. 建立唯一性烦引�?/p>

CREATE UNIQUE INDEX I_ztables_tabname

[size=3]ON zjt_tables(tabname);

9. 查看表�?/p>

select tabname from tables

where tabname='ZJT_TABLES';

10. 查看列�?/p>

select SUBSTR(COLNAME,1,20) as 列名,TYPENAME as �c�d��,LENGTH as 长度

from columns

where tabname='ZJT_TABLES';

11. 查看表结构�?/p>

db2 describe table user1.department

db2 describe select * from user.tables

12. 查看表的索引

db2 describe indexes for table user1.department

13. 查看视图

select viewname from views

where viewname='V_ZJT_TABLES';

14. 查看索引

select indname from indexes

where indname='I_ZTABLES_TABNAME';

15. 查看存贮�q�程

SELECT SUBSTR(PROCSCHEMA,1,15),SUBSTR(PROCNAME,1,15)

FROM SYSCAT.PROCEDURES;

16. �c�d��转换(cast)

ip datatype:varchar

select cast(ip as integer)+50 from log_comm_failed

17. 重新�q�接

connect reset

18. 中断数据库连接�?/p>

disconnect db2_gcb

19. view application

LIST APPLICATION;

20. kill application

FORCE APPLICATION(0);

db2 force applications all (��所有应用程序从数据库断开)

21. lock table

lock table test in exclusive mode

22. �׃�n

lock table test in share mode

23. 昄��当前用户所有表

list tables

24. 列出所有的�pȝ��表�?/p>

list tables for system

25. 昄��当前�z�d��数据库�?/p>

list active databases

26. 查看命��o选项

list command options

27. �pȝ��数据库目录�?/p>

LIST DATABASE DIRECTORY

28. 表空闾b?/p>

list tablespaces

29. 表空间容器�?/p>

LIST TABLESPACE CONTAINERS FOR

Example: LIST TABLESPACE CONTAINERS FOR 1

30. 昄��用户数据库的存取权限

GET AUTHORIZATIONS

31. 启动实例

DB2START

32. 停止实例

db2stop

33. 表或视图�Ҏ(gu��)��

grant select,delete,insert,update on tables to user

grant all on tables to user WITH GRANT OPTION

34. �E�序包特权�?/p>

GRANT EXECUTE

ON PACKAGE PACKAGE-name

TO PUBLIC

35. 模式�Ҏ(gu��)��

GRANT CREATEIN ON SCHEMA SCHEMA-name TO USER

36. 数据库特权�?/p>

grant connect,createtab,dbadm on database to user

37. 索引�Ҏ(gu��)��

grant control on index index-name to user

38. 信息帮助 (? XXXnnnnn )

�?? SQL30081

39. SQL 帮助(说明 SQL 语句的语�?

help statement

例如�Q�help SELECT

40. SQLSTATE 帮助(说明 SQL 的状态和�c�d��代码)

? sqlstate 或�? class-code

41. 更改�?��理服务�?相关的口令�?/p>

db2admin setid username password

42. 创徏 SAMPLE 数据库�?/p>

db2sampl

db2sampl F:(指定安装�?

43. 使用操作�pȝ��命��o

! dir

44. 转换数据�c�d�� (cast)

SELECT EMPNO, CAST(RESUME AS VARCHAR(370))

FROM EMP_RESUME

WHERE RESUME_FORMAT = 'ascii'

45. UDF

要运行 DB2 Java 存储�q�程或 UDF�Q�还需要更新服务器上的 DB2 数据库管理程序配�|�，以包括在该机器上安装 JDK 的�\径�?/p>

db2 update dbm cfg using JDK11_PATH d:sqllibjavajdk

TERMINATE

update dbm cfg using SPM_NAME sample

46. ��查 DB2 数据库管理程序配�|��?/p>

db2 get dbm cfg

47. ��索具有特权的所有授权名

SELECT DISTINCT GRANTEE, GRANTEETYPE, 'DATABASE' FROM SYSCAT.DBAUTH

UNION

SELECT DISTINCT GRANTEE, GRANTEETYPE, 'TABLE ' FROM SYSCAT.TABAUTH

UNION

SELECT DISTINCT GRANTEE, GRANTEETYPE, 'PACKAGE ' FROM SYSCAT.PACKAGEAUTH

UNION

SELECT DISTINCT GRANTEE, GRANTEETYPE, 'INDEX ' FROM SYSCAT.INDEXAUTH

UNION

SELECT DISTINCT GRANTEE, GRANTEETYPE, 'COLUMN ' FROM SYSCAT.COLAUTH

UNION

SELECT DISTINCT GRANTEE, GRANTEETYPE, 'SCHEMA ' FROM SYSCAT.SCHEMAAUTH

UNION

SELECT DISTINCT GRANTEE, GRANTEETYPE, 'SERVER ' FROM SYSCAT.PASSTHRUAUTH

ORDER BY GRANTEE, GRANTEETYPE, 3

create table yhdab

(id varchar(10),

password varchar(10),

ywlx varchar(10),

kh varchar(10));

create table ywlbb

(ywlbbh varchar(8),

ywmc varchar(60))

48. 修改表结构�?/p>

alter table yhdab ALTER kh SET DATA TYPE varchar(13);

alter table yhdab ALTER ID SET DATA TYPE varchar(13);

alter table lst_bsi alter bsi_money set data type int;

insert into yhdab values

('20000300001','123456','user01','20000300001'),

('20000300002','123456','user02','20000300002');

49. 业务�c�d��说明

insert into ywlbb values

('user01','业务甌��'),

('user02','业务撤消'),

('user03','费用查询'),

('user04','费用自缴'),

('user05','费用预存'),

('user06','密码修改'),

('user07','发票打印'),

('gl01','改用户基本信�?),

('gl02','更改支付信息'),

('gl03','日统计功�?),

('gl04','冲帐功能'),

('gl05','对帐功能'),

('gl06','计费功能'),

('gl07','�l�合�l�计')

备䆾数据库：
CONNECT TO EXOA;
QUIESCE DATABASE IMMEDIATE FORCE CONNECTIONS;
CONNECT RESET;
BACKUP DATABASE EXOA TO "/home/exoa2/db2bak/" WITH 2 BUFFERS BUFFER 1024 PARALLELISM 1 WITHOUT PROMPTING;
CONNECT TO EXOA;
UNQUIESCE DATABASE;
CONNECT RESET;

以下是小弟在使用db2move中的一些经验，希望对大家有所帮助。�?/p>

db2 connect to YOURDB
�q�接数据库�?/p>

db2look -d YOURDB -a -e -x -o creatab.sql
导出建库表的SQL

db2move YOURDB export
用db2move��数据备份出来�?/p>

vi creatab.sql
如要导入的数据库名与原数据库不同�Q�要修改creatab.sql中CONNECT ��?br />如相同则不用更改

db2move NEWDB load
��数据导入新库中

在导入中可能因�ؓ�U�种原因发生中断�Q�会使数据库暂挂
db2    list tablespaces   show   detail
如：
      详细说明�Q��?br />     装入暂挂
总页敊W�                        �? 1652
可用��|��                        = 1652
已用��|��                         = 1652
�I�闲��|��                         = 不适用
高水位标讎ͼ��）                 = 不适用
��大��（字节�Q�                  �? 4096
盘区大小�Q�页�Q�                  �? 32
预读取大��（��）                 = 32
容器敊W�                         �? 1
状态更改表�I�间标识                    = 2
状态更改对象标识                     �? 59

db2 select tabname,tableid from syscat.tables where tableid=59
查看是哪张表挂�v

表名知道后到db2move.lst(在db2move YOURDB export的目录中)中找到相应的.ixf文�g
db2 load from tab11.ixf of ixf terminate into db2admin.xxxxxxxxx
tab11.ixf对应的是xxxxxxxxx表�?/p>

数据库会恢复正常�Q�可再用db2 list tablespaces show detail查看

30.不能通过GRANT授权的权限有哪种?

SYSAM

SYSCTRL

SYSMAINT

要更该述权限必须修改数据库管理器配置参数

31.表的�c�d��有哪�?

�怹��?��)

临时�?说明�?

临时�?�z��?

32.如何知道一个用��h��多少�?

SELECT*FROMSYSIBM.SYSTABLESWHERECREATOR='USER'

33.如何知道用户下的函数?

select*fromIWH.USERFUNCTION

select*fromsysibm.SYSFUNCTIONS

34.如何知道用户下的VIEW�?

select*fromsysibm.sysviewsWHERECREATOR='USER'

35.如何知道当前DB2的版�?

select*fromsysibm.sysvERSIONS

36.如何知道用户下的TRIGGER�?

select*fromsysibm.SYSTRIGGERSWHERESCHEMA='USER'

37.如何知道TABLESPACE的状�?

select*fromsysibm.SYSTABLESPACES

38.如何知道SEQUENCE的状�?

select*fromsysibm.SYSSEQUENCES

39.如何知道SCHEMA的状�?

select*fromsysibm.SYSSCHEMATA

40.如何知道INDEX的状�?

select*fromsysibm.SYSINDEXES

41.如何知道表的字段的状�?

select*fromsysibm.SYSCOLUMNSWHERETBNAME='AAAA'

42.如何知道DB2的数据类�?

select*fromsysibm.SYSDATATYPES

43.如何知道BUFFERPOOLS状况?

select*fromsysibm.SYSBUFFERPOOLS

44.DB2表的字段的修攚w��?

只能修改VARCHAR2�c�d��的�ƈ且只能增加不能减��?

45.如何查看表的�l�构?

DESCRIBLETABLETABLE_NAME

DESCRIBLESELECT*FROMSCHEMA.TABLE_NAME

MyJavaWorld 2006-12-28 16:57 发表评论

MyJavaWorld — Fri, 08 Dec 2006 10:12:00 GMT

DB2 UDB中用户出口程序是如何工作的？

采用用户出口�E�序与DB2 UDB共同工作背后的基本思想是提供一�U�归档和��索数据库日志文�g的方法以实现日志冗余处理�q�从易失性介质上转储出来。重要的�Q�值得注意的是�Q�根据你的特�D�需求，在用户出口程序当中，除了能实现归��和��索日志之外，你还可以实现其他的操作�?/p>

如果一个数据库需要采用归档日志文件来�q�行恢复�Q�在DB2 UDB中实行用户出口程序策略将不能恢复100%的事务。用户出口程序只是一�U�通过拯��已经存在的日志文件到一个安全的地方来�ؓ其提供更多保护的�Ҏ(gu��)��。它是数据完整性策略中的一部分�Q�而且是重要的一部分�?/p>

�~�译了用户出口程序之后，可执行程序db2uext2被放�|�在数据库管理器可以扑ֈ�的目录当中。在UNIX©中，�q�个目录�?instance home="" />/sqllib/adm�Q�在Windows©中，�?drive letter="" />Program FilesIBMSQLLIBBIN�?/p>

除非数据库管理器知道用户出口�E�序是可用的�Q�不然它不会调用db2uext2。让数据库管理器知道db2uext2可以被调用的唯一�Ҏ(gu��)��是将数据库配�|�参数userexit讄��为on。一旦这个参数被讑֮�好而且DB2实例被重复利用了�Q�数据库��理器将每五分钟调用一�ơ用户出口程序来��查那些可以被归档到程序相关的归档目录的日志文件�?/p>

如果数据库的恢复是必要的�Q�在前滚操作期间�Q�数据库��理器将调用db2uext2把归��日志文件拷贝回�z�d��的日志目录当中。然后，日志文�g被再�ơ运用到重徏的数据库中�?/p>

让我们看看被数据库管理器生成的到用户出口�E�序的调用的格式。注意，�q�一信息也可以在用户出口�C�Z��E�序的注释部分找到�?/p>

db2uext2 -OS -RL

-RQ -DB -NN

-LP -LN [-AP]

其中�Q?/p>

os=操作�pȝ��

release=DB2发行版本

request= 'ARCHIVE' �?'RETRIEVE'

dbname=数据库名

nodenumber=节点�?/p>

logpath=日志文�g目录

logname=日志文�g�?/p>

logsize=日志文�g大小�Q�可选）

startingpage=�?k��ؓ单位的�v始偏�U�量�Q�可选）

adsmpasswd=ADSM密码�Q�可选）

注意�Q�只有当logpath��讑֤�时才使用logsize和startingpage�?/p>

归��或者从��盘?g��u)��索日志文仉��从以下命名规则：

归��Q�归��\径＋数据库名�Q�节点号�Q�日志文件名

��索：��索�\径＋数据库名�Q�节点号�Q�日志文件名

比如�Q�如果归��的路径为”c:mylogs�?

��索�\径是“c:mylogs”，

数据库名是“SAMPLE”，

节点��h�� NODE0000�Q?/p>

文�g名是 S0000001.LOG�Q?/p>

日志文�g��是�Q?/p>

归档�?- c:mylogsSAMPLENODE0000S0000001.LOG

��索自 - c:mylogsSAMPLENODE0000S0000001.LOG

以下描述了用户出口程序中的逻辑是如何运转的�Q?/p>

1) 安装信号处理�E�序�?/p>

2) 验证传递的参数个数�?/p>

3) 验证操作��h��?/p>

4) 开始审计跟�t�（如果有此��h��Q��?/p>

5) �Ҏ(gu��)��操作需求的不同获取以下路径中的一个：

a) 如果操作需求�ؓ归档一个文�Ӟ��日志文件从日志路径拯��到归档�\径中�?/p>

i�Q?如果没有扑ֈ�日志文�g�Q�执行第6炏V�?/p>

b) 如果操作需求是��索一个文�Ӟ��日志文件从��索�\径拷贝到日志路径中�?/p>

i�Q?如果没有扑ֈ�日志文�g�Q�执行第6炏V�?br />
6) ��错误记入日志（如果要求或者有需要的话）�?/p>

7) �l�束审计跟踪�Q�如果有��h��Q��?/p>

8) 以适当的返回码退出�?/p>

手工调用用户出口�E�序来归��日志文件是可以的，但最好还是��用ARCHIVE LOG命��o以便在定义以上参数时不会因�ؓ你的原因��D��错误。在�q�篇文章的末��，可以扑ֈ�关于ARCHIVE LOG命��o的链接�?/p>

日志文�g术语

DB2 中用户出口程序的基本功能是将日志文�g拯��到活动日志目录或反之。这里，值得指出一些术语来阐明�z�d��的日志目录被�|�于何处以及数据库日志文件的状态如何�?/p>

�z�d��日志目录�Q?/b>

该目录被�|�于你的数据库目录中。在Windows中，如果在C:中创��Z��一个叫做SAMPLE的单一数据库且实例名�ؓdb2inst1�Q�则��会出现以下的目录结构：

C:DB2INST1NODE0000SQL000001SQLOGDIR

SQL00001是SAMPLE数据库的数据库目录，SQLOGDIR 是活动日志目录�?/p>

以下的图1昄��了Windows操作�pȝ��上的�z�d��日志目录�Q?/p>

PATH o:extrusionok="f" gradientshapeok="t" o:connecttype="rect" />SHAPE id=_x0000_i1025 style="WIDTH: 299.25pt; HEIGHT: 180.75pt" type="#_x0000_t75" />/P>

�?1�z�d��日志目录

日志文�g状�?/b>

在活动日志目录中�Q�日志文件可以是�z�d��日志�Q�也可以是联机归��日志。活动日志是那些�?DB2 用于当前事务处理和崩溃恢复的日志。联机归��日志是那些 DB2 UDB �q�行常规处理时不再需要，而进行数据库恢复时可能还会需要的日志。当实现用户出口�E�序�Ӟ��q�些联机归��日志��最�l�以归档日志目录中的副本形式出现�?/p>

既然 DB2 UDB 中用户出口程序的目的是将数据库日志拷贝到归��目录中，你将最�l�在�z�d��日志目录�Q�缺省�ؓ SQLOGDIR�Q�中得到重复的日志文件。你可能考虑删除�q�些重复的联机归��日志以释放文�g�pȝ��I�间。在从数据库目录中除去这些日志之前，要十分小心地��认它们是否已经��成功地被复制到归��目录中。还必须��保数据库管理器�q�行崩溃恢复时不再需要它们。要��定你的�z�d��日志目录中哪些日志文件不为正常处理所需要，可用通过以下命��o��查数据库配置�Q?/p>



     db2 "get db cfg for sample"

�q�条命��o的数据库配置输出�l�果��包含第一个活动日志文�Ӟ��如：

First active log file = S000009.LOG

在如上所�C�的输出当中�Q�日志文件S000009.LOG是数据库当前的活动日志。�Q何编��h��该日志文件小的日志文仉��被看作联机归��日志�?/p>

�q�里有一个例子：

在这个场景中�Q�活动日志目录中有日志文�?S000000.LOG - S000009.LOG�Q�归��日志目录中�?S000000.LOG - S000008.LOG。因�?S000009.LOG 是第一个活动日志文�Ӟ��所以，可以从活动日志目录中�U�走 S000001.LOG - S000008.LOG 以释攄��盘空间。S000009.LOG 文�g必须保留在活动日志目录中�Q�因为它仍然被当前事务��用�?/p>

同样可以通过��查数据库历史文�g来查看活动日志目录中哪些日志文�g不再有用。以下命令将列出数据库备份信息：

     db2 "list history backup all for database sample"

以下是该命��o的输出结果的一个例子：

List History File for sample

Number of matching file entries = 4

Op Obj Timestamp+Sequence Type Dev Earliest Log Current Log

-- --- ------------------ ---- --- ------------------------

B D 20030416162026001 F D S0000010.LOGS0000014.LOG

------------------------------------------------------------

Contains 2 tablespace(s):

00001 SYSCATSPACE

00002 USERSPACE1

------------------------------------------------------------

在上面的输出中，最早的日志��表�C�，需�?S0000010.LOG 及其之后的�Q何日志�?S00000010.LOG 之前的�Q何日志可以被安全的删除。再�ơ提醒，在从�z�d��日志目录中删除日志文件之前，验证在活动日志目录中存在�q�些日志文�g的拷贝是十分重要的�?/p>

虽然可以手动的从�z�d��日志目录中删除日志文�Ӟ��删除联机归��日志文�g的安全方法是通过prune logfile命��o。该命��o可以用来删除�z�d��归��目录中的日志文�g。在下面的示例中�Q�以下命令将删除日志文�g S000000.LOG - S000008.LOG�Q?/p>

     db2 "prune logfile prior to S000009.LOG"

注意�Q?/b>�Ҏ(gu��)��(zh��n)�的恢复�{�略�Q�可能会出现之前的前滚操作在数据库上执行的场景。归��目录中的老日志文件可能被同名的新日志文�g所覆盖�Q�从而阻止你使用旧日志文件对数据库进行时间点恢复。对用户出口�E�序的设计程序员来说�Q�考虑�c�M��q�样的情冉|��很重要的�?/p>

讄��用户出口

在本文中�Q�我们将采用DB2提供的db2uext2.cdisk样例c�E�序�Q�它位于你的c目录当中。在UNIX中，c目录位于/sqllib/samples。Windows中，�q�目录位于Program Files/IBM//samples�?/p>

在Windows中设�|�用户出�?/b>

修改和编译用户出口程�?/b>

1. 创徏名�ؓC:mylogs的目�?/p>

2. ��C:Program filesIBMSQLLIBsamplescdb2uext2.cdisk拯��C��个工作目录当�?/p>

3. 对于本示例，用户出口�E�序的以下部分应该得以验证以反映路径 c:\mylogs\

#define ARCHIVE_PATH "c:\mylogs\"

#define RETRIEVE_PATH "c:\mylogs\"

#define AUDIT_ACTIVE 1 /* enable audit trail logging */

#define ERROR_ACTIVE 1 /* enable error trail logging */

#define AUDIT_ERROR_PATH "c:\mylogs\"

                 /* path must end with a slash */

#define AUDIT_ERROR_ATTR "a" /* append to text file */

#define BUFFER_SIZE 32

    /* # of 4K pages for output buffer */

4. ��定在你的系�l�中安装了被支持的C�~�译器（比如�Q�Microsoft Visual Studio�Q�而且环境中有该编译器的�\径�?/p>

5. 通过命��o行，��db2uext2.cdisk更名为db2uext2.c�q�构建：

cl db2uext2.c

一旦程序被�~�译�Q�将创徏db2uext2.exe和db2uext2.obj文�g�?/p>

6. ��可执行文�gdb2uext2.exe攑ֈ�/SQLLIB/BIN目录当中从而��数据库管理器能够定位�q�执行它用以归档和检索日志�?/p>

为用户出口创建�ƈ准备数据�?/b>

7. �?DB2 命��o�H�口中用 db2sampl 命��o创徏 SAMPLE 数据库。这��你对下面的示例��用样本表�?/p>

db2sampl

8. 更新数据库配�|�文件以便�ؓ数据库打开用户出口。请注意�Q�只能�ؓ一个数据库分配用户出口�E�序�Q�因�?bin 目录被所�?DB2 实例�׃�n�?/p>

db2 "update db cfg for sample using userexit on"

db2stop force

MyJavaWorld 2006-12-08 18:12 发表评论

如何使用keytool创徏密钥仓库 (�?

MyJavaWorld — Tue, 31 Oct 2006 09:18:00 GMT

其实主要的就是要创徏一个密钥仓库以��理�(zh��n)�的公钥 / �U�钥�Ҏ(gu��)��自�?zh��n)�所信�Q实体的证书�?br />
�W�一步：生成密钥�?/span>
�(zh��n)�首先要做的是创��Z��个密钥仓库和生成密钥寏V��?zh��n)�可以使用以下命��o�Q?/span>
keytool -genkey -keyalg RSA -keysize 512 -dname "cn=hyq,o=eagle,c=cn" -alias weblogic -keypass 123456 -keystore C:/mykeystore/weblogic.jks -storepass 123456 -validity 365
�Q�请注意�Q�键入该命��o时必��M��其成��Z��行。此处用多行来显�C�，主要是�ؓ了可��L��。）如下图：

该命令将�?/span> C 盘的 “mykeystore�?/span> 目录中创建名�?/span> “weblogic.jks�?/span> 的密钥仓库，�q�赋予它口��o �?/span> 123456 �?/span> 。它?y��u)��ؓ实体生成公�?/span> / �U�钥对，该实体的 �?/span> 特征�?/span> �?/span> 为：常用�?/span> “hyq�?/span> 、组�l?/span> “eagle�?/span> 和两个字母的国家代码 “cn�?/span> 。�?/span> -keyalg ”指定它使用的是那种密钥生成��法来创建密钥，�~�省的是 “DSA�?/span> 密钥生成��法�Q�会使用�~�省�?/span> �?/span> �?/span> DSA �?/span> SHA�{�֐��法�Q�，两个密钥�Q�公钥与�U�钥�Q�的长度�?/span> 512 位，�?/span> -keysize 来指定，默认的是 1024 位�?/span> 该证书包括公钥和特征名信息。该证书的有效期�?/span> 365 天，�?/span> -validity 来指定，且与别名 “business�?/span> 所代表的密钥仓库项兌��。私钥被赋予口��o �?/span> 123456 �?/span> �?/span>

命��o行里 DName 信息注解

DN 信息�?/span>

含义

CN

域名�?/span> IP

OU

部门�Q�没有部门的可不要此��?/span>

O

单位名称

L

单位地址

S

省䆾的拼韻I��W�一个字母大写）

C

国家的简�?�Q?/span> CN 代表中国�Q?/span>

如果采用选项的缺省��|��可以大大�~�短该命令。实际上�Q�这些选项�q�不是必需的；对于有缺省值的选项�Q�未指定时将使用�~�省��|��对于��M��被要求的��|��(zh��n)�将会得到要求输入它的提�C�。例如：输入命��o keytool -genkey -keystore "C:/tone.jks" -storepass 123456 -keyalg RSA �Q�就会有如下提示�Q?br />

注意�Q�这里的密钥仓库路径一定要存在�Q�如果不存在的话�Q�它?y��u)�׃��抛如下的异�?br />

�W�二�?/span> : 产生证书��h��certreq.pem 文�g

使用如下命��o�Q?span lang="EN-US">

keytool -certreq -alias weblogic -sigalg "MD5withRSA" -file C:/mykeystore/certreq.pem -keypass 123456 -keystore C:/mykeystore/weblogic.jks -storepass 123456

�q�样�?/span> C:/mykeystore/ 目录�?/span> ��׃��产生一�?/span> certreq.pem 文�g�Q�内容如下：

-----BEGIN NEW CERTIFICATE REQUEST-----

MIHlMIGQAgEAMCsxCzAJBgNVBAYTAmNuMQ4wDAYDVQQKEwVlYWdsZTEMMAoGA1UEAxMDaHlxMFww

DQYJKoZIhvcNAQEBBQADSwAwSAJBAMhaIG2Ki7+RwZUP4gPBdTbnY38bisW16u1XUyysPxdNwSie

aSd6E3Hm277E7NjHoz56ZoaYdPPDmdiTkMrS9rcCAwEAAaAAMA0GCSqGSIb3DQEBBAUAA0EAYRNl

l5dyGgV9hhu++ypcJNQTrDIwjx1QT4fgVubrtIaHU0fzHamD5QG6PYddw9TL51XQHvu6tOS0NUc/

ItNKJw==

-----END NEW CERTIFICATE REQUEST-----

�W�三步：�q�就相对来说��单多了，��是�?span lang="EN-US">CA提交证书��h��?br />    你可以随便从�|�上找一家免费的CA认证适用机构�Q�很多的�Q�，然后按照上面的提�C��行操作就可以了，�q�一步就要用到前面生成的certreq.pem 文�g�?/font>。（注意�Q�一定要下蝲根证书）
    ��生成的证书和下载的根证书放至你比较�Ҏ(gu��)��扑ֈ�的位�|�，我一般将它们和生成的jks文�g攑ֈ�一赗��?br />
�W�四步：导入证书
    通过命��o�Q�keytool -import -alias RootCA -trustcacerts -file C:/mykeystore/RootCADemo.cer -keystore C:/mykeystore/weblogic.jks -storepass 123456��根证书导入�W�一步生成的weblogic.jks中，接着��所有其它的证书按照此命令全部导入。（注意证书的别名不能重复，同时一�?strong>注意要用�?-trustcacerts�Q�否则，你在以后使用�Ӟ��它将会认��Z��导入的这些证书是不可信�Q�?�Q�就会导致你在配�|�SSL时不能正常的工作。）
    �q�就全部完成�?font size="3">密钥仓库的创建。然后就可以在支持这些证书格式的服务器上使用了。下一��将会写一下在weblogic上如何配�|�双向SSL

MyJavaWorld 2006-10-31 17:18 发表评论

MyJavaWorld — Tue, 22 Aug 2006 04:07:00 GMT
现在的DB2 UDB�pȝ��中，主要通过锁和隔离�U�别�q�两个主要的工具来控制�ƈ发连接，�l�护数据库中的数据在高�ƈ发的环境下的安全�?
我们在这里将��要的阐述一下锁和隔��ȝ�别�?/p>
锁：
DB2 UDB中，锁的主要作用对象是表和行�Q?其他如表�I�间和烦引也是锁的对象，但是因�ؓ其多为系�l�控�Ӟ�� 理员和用户使用较少�Q�在�q�里��׃��涉及了�?
对于行��锁和表��锁，它们的区别不�a�而喻�Q?主要是锁的对象不同�?当然锁对象的不同�q�带也会影响DB2的�ƈ发能力�?
DB2中的表��锁主要有以下几种�Q?/p>
1�Q?IS锁：此锁作用于整个表�Q�表�C�拥有此锁的应用�q�接要读取表中的某些数据�Q?但是在此应用�q�接��d��具体的数据时�Q?�q�必��获得该行的行��锁；
2�Q?IX锁：此锁作用于整个表�Q�表�C�拥有此锁的应用�q�接需要独占��用表中的某些数据�Q?但是在此应用�q�接独占使用具体的数据时�Q?�q�必��获得该行上相应的行�U�锁�Q?/p>
3�Q?SIX锁：此锁是锁转换的��物，表示应用�q�接拥有S和IX锁的�Ҏ(gu��)��；
4�Q?S锁：此锁作用于整个表�Q?拥有此锁的应用连接可以读取表中的��M��U�录�Q?/p>
5�Q?U锁：此锁作用于整个表�Q?拥有此锁的应用连接可以读取表中的��M��U�录�Q�也可以更新表中的纪录，但是更新旉��要再获得X锁；此锁主要在“select �?with update”语句徏立的可更新游标中起作用，其他的应用可以读取表中的�U�录�Q?但是不能更新它；
6�Q?X锁：此锁作用于整个表�Q?拥有此锁的应用连接独占的使用表中的�Q何纪录；可以�q�行更新或其他操作；
7�Q?Z锁：此锁作用于整个表�Q?也称��独占锁，主要是在象修改表的定义�?删除表这一�cȝ��语句中会使用�?拥有此锁的应用连接对该表有完全的控制权�?其他的�Q何应用不能读取或更新表中的�Q何纪录�?/p>
在这里我们主要要看一�?IS/IX/SIX�q�三个锁�?在这三个锁中IS/IX本��n�q�不具备使得应用�q�接可以��d��或更新纪录的能力�Q�应用连接要��d��和更新纪录时�Q?需要再得到相应的行�U�锁�Q?反之亦然�Q?��M��应用要获得行�U�锁操作数据记录之前�Q?也必��获得某个相应的表��锁�?SIX锁也是类似的情况。这��是��Z��麽在很多情况下我们��用的是行�U�锁�Q?但是用快照（SNAPSHOT�Q�等工具却能够看到有表��锁存在的原因�?/p>
那麽DB2中又有哪些行�U�锁呢？让我们来看下面的�q�张图：

此图中列��Z��DB2中包含的行��锁�?表中的第三列指出�Q?要获得此行��锁之前，需要预先获得的表��锁， �q�里列出的是最低要求�?/p>
�q�六个行�U�锁的主要功能如下：
1�Q?S锁：此行�U�锁的拥有者可以读取该行的信息�Q?
2�Q?U锁：此行�U�锁的拥有者可以读取该行的信息�Q�如果要更新该行�Q�则仍然需要一个行�U�的X锁；其他的应用只能读取该行的信息�Q�此锁主要是用于FOR UPDATE的游标�?/p>
3�Q?X锁：此行�U�锁的拥有者可以更新该行的�U�录�Q�其他的应用不能�q�接此行的信息；
4�Q?W锁：此锁和X锁类��|��不同之处是此锁和NW锁兼容；
5�Q?NS锁：�c�M��于S锁，用于Next Key�Q?/p>
6�Q?NW锁：�c�M��于W锁，用于Next Key�Q?/p>
在DB2数据库中�Q?是通过行��锁和表��锁协调作用来提供较好的�ƈ发性，同时保证数据库中数据的安全�?在DB2中缺省情况下使用行��锁（当然需要IS/IX锁配合）�Q�只有当出现锁资源不��I�� 或者是用命令指定��用表�U�锁的情况下�Q?才会在应用连接中使用表��锁�?寚w��资源分配有兴��的读者可以参考DB2的管理手册，查找其中关于locklist和maxlocks参数的论�q�。对于用命��o指定表��锁的情况�Q?可以参考DB2的命令手册中的lock table命��o�Q?此命令用于直接锁表�?/p>
隔离�U�别�Q?/p>
下面让我们来看一下隔��ȝ�别�?隔离�U�别主要用于控制在DB2�Ҏ(gu��)��应用提交的SQL语句向DB2数据库中的相应对象加锁时�Q?会锁住哪些纪录，也就是锁定的范围�?隔离�U�别的不同，锁定的纪录的范围可能会有很大的差别�?/p>
隔离�U�别分�ؓRR/RS/CS/UR�q�四个��别�?下面让我们来逐一��Q?/p>
1�Q?RR隔离�U�别�Q?在此隔离�U�别下， DB2会锁住所有相关的�U�录�?在一个SQL语句执行期间�Q?所有执行此语句扫描�q�的�U�录都会被加上相应的锁�?具体的锁的类型还是由操作的类型来军_��Q?如果是读取，则加�׃�n锁；如果是更斎ͼ� 则加独占锁�?�׃��会锁定所有�ؓ获得SQL语句的结果而扫描的�U�录�Q?所以锁的数量可能会很庞大， �q�个时候，索引的增加可能会对SQL语句的执行有很大的媄响，因�ؓ索引会媄响SQL语句扫描的纪录数量�?/p>
2�Q?RS隔离�U�别�Q?此隔��ȝ�别的要求比RR隔离�U�别�E�弱�Q�此隔离�U�别下会锁定所有符合条件的�U�录�?不论是读取， �q�是更新�Q?如果SQL语句中包含查询条�Ӟ�� 则会�Ҏ(gu��)��有符合条件的�U�录加相应的锁�?如果没有条�g语句�Q?也就是对表中的所有记录进行处理，则会�Ҏ(gu��)��有的�U�录加锁�?/p>
3�Q?CS隔离�U�别�Q?此隔��ȝ�别仅锁住当前处理的纪录�?
4�Q?UR隔离�U�别�Q�此隔离�U�别下，如果是读取操作，不会出现��M��的行�U�锁。对于非只读的操作，它的锁处理和CS相同�?/p>
在这四种隔离�U�别中， CS是缺省倹{�?�q�四�U�隔��ȝ�别均可以保证DB2数据库在�q�发的环境下不会有数据丢��q��情况发生�?要注意的是如果对�U�录�q�行了修改，需要在相应的纪录上加独占类型的锁， �q�些独占�c�d��的锁直到交易�l�束时才会被释放�Q?�q�一点在四种隔离�U�别下都是相同的�?/p>

MyJavaWorld 2006-08-22 12:07 发表评论

REORG TABLE

MyJavaWorld — Wed, 26 Jul 2006 14:10:00 GMT

REORG TABLE

REORG TABLE 语句压羃与指定的表相兌��的数据�?

调用

此语句可以在使用 DB2 CLI 函数的应用程序中使用�Q�也可以通过 CLP 发出�?

语法

>>-REORG TABLE--table-name--+------------+--------------------->< '-int1--int2-'

描述

REORG TABLE table-name

标识重组操作的表。名�U�必��L��识现有的表�?

int1

需要恢复的字节的可选最��百分比�?

int2

需要�ؓ��要执行的表压羃恢复的最��字节数�?

规则

可选的�?int1 �?int2 必须一起��用，或全都不用�?

可选的�?int1 必须是非负数�?

可选的�?int1 必须介于 0 �?100 之间�?

注意事项

DB2 Everyplace 可以以内部方式调用表重组�?

�W�一个可选参数是表必��d��含的不可用的字节的百分比�Q�即癑ֈ�之十�Q?0�Q�意味“至��百分之十的�I�间不可用”。）�W�二个可选参数是表必��d��含的不可用的字节敎ͼ��?1000 ��意味“至��?1000 个字节必��L��不可用的�I�间”。）必须�W�合两个条�g�Q�才可以�q�行表的实际重组�?

如果没有指定参数�Q�DB2 Everyplace 对这此选项使用�~�省倹{��缺省百分比�?30 且缺省字节是 6144。因此，“reorg table t1”与“reorg table t1 30 6144”相同�?

如果重组方式讄��为已启用�Q�则 DB2 Everyplace ��自动重�l�表。如果在 DELETE �?UPDATE 上启用了重组�Q�则在执行语句之后，会对目标表执行“reorg table table_name 50 30270”。如果在 DROP TABLE 上启用了重组�Q�则在删除表处理�l�束时执行“reorg table DB2eSYSTABLES 30 10240”（对于 DB2eSYSCOLUMNS �?DB2eSYSRELS 也是如此�Q��?

�?C/C++ �E�序中，通过使用��h��属�?SQL_ATTR_REORG_MODE �?CLI/ODBC 函数 SQLSetStmtAttr 讄��重组方式。在 JAVA �E�序中，通过 DB2eStatement 接口 enableReorg �Ҏ(gu��)��讄��重组方式。缺省值是启用重组�?

重组表时�Q�通过物理上回收删除和更新创徏的不可用�I�间来压�~�包含表的数据文件。然后将表的索引更新为指向行的新物理位置�?

可以重组“DB2 Everyplace �pȝ��目录”基本表�?

在执�?REORG TABLE 语句�Ӟ��数据库中不应发生��M��其它�z�d��?

�C�Z��

使用�~�省值压�~?VNNURSE 表�?

REORG TABLE VNNURSE

MyJavaWorld 2006-07-26 22:10 发表评论

DB2 存储�q�程问题(�?

MyJavaWorld — Fri, 21 Jul 2006 02:03:00 GMT
     摘要: 在数据库应用�E�序中��用存储过�E�有许多好处�Q�包括减��对�|�络的��用、提高性能以及降低开发成本。Java 存储�q�程�?DB2 支持的最��行的例�E�之一。原因之一是，�׃�� Java �~�程语言非常��行�Q�所�?Java 开发�h员非常多。因此，在有多种语言可供选择�Ӟ��Java 例程往往是首选的�? DB2 存储�q�程不一定非�?Java 来编写。如果业务逻辑只需要简单的存储�q�程�Q�那么可以考虑�?...  阅读全文

MyJavaWorld 2006-07-21 10:03 发表评论

MyJavaWorld — Thu, 20 Jul 2006 07:48:00 GMT

J***A正则表达�?/h1>
关键�?/b>�Q?正则表达�?/a>
正则表达�?/h2>
。正则表辑ּ�(regular expression)�?span class="original_words">JDK 1.4的新功能�Q�但是对sed和awk�q�样的Unix的标准实用工��P��以及Python�Q�Perl之类的语�a�来讲�Q�它早就已经成�ؓ其不可或�~�的�l�成部分�?有�h甚至认�ؓ�Q�它�q�是Perl能大��h��功的最主要的原�?。单从技术角度来�Ԍ��正则表达式只是一�U�处理字�W�串的工�?�q�去Java�q�个��d��是交�?span class="original_words">String�Q?span class="original_words">StringBuffer以及StringTokenizer处理�?�Q�但是它常常和I/O一起��用，所以放到这里来讲也不算太离题吧�?/p>
正则表达式是一�U�功能强大但又非常灵�zȝ��文本处理工具。它能让你用�~�程的方式来描述复杂的文本模式，然后在字�W�串里把它找出来。一旦你扑ֈ�了这�U�模式，你就能随心所�Ʋ地处理�q�些文本了。虽然初看�v来正则表辑ּ�的语法有点让人望而生畏，但它提供了一�U�精�l�的动态语�a��Q��我们能用一�U�通用的方式来解决各种字符串的问题�Q�包括匹配，选择�Q�编辑以及校验�?/p>
创徏正则表达�?/h3>
你可以从比较��单的东西入手学习(f��n)正则表达式。要惛_��面地掌握怎样构徏正则表达式，可以�ȝ��JDK文��?span class="original_words">java.util.regex�?span class="original_words">Pattern�cȝ��文��?/p>
字符
B 字符B
\xhh 16�q�制�?span class="original_words">0xhh所表示的字�W?/td>
\uhhhh 16�q�制�?span class="original_words">0xhhhh所表示的Unicode字符
\t Tab
\n 换行�W?/td>
\r 回�R�W?/td>
\f 换页�W?/td>
\e Escape
正则表达式的强大体现在它能定义字�W�集(character class)。下面是一些最常见的字�W�集及其定义的方式，此外�q�有一些预定义的字�W�集�Q?/p>
字符�?/span>
. 表示��L��一个字�W?
[abc] 表示字符a�Q?span class="original_words">b�Q?span class="original_words">c中的��L��一�?�?span class="original_words">a|b|c相同)
[^abc] �?span class="original_words">a�Q?span class="original_words">b�Q?span class="original_words">c之外的�Q意一个字�W?否定)
[a-zA-Z] �?span class="original_words">a�?span class="original_words">z�?span class="original_words">A�?span class="original_words">Z当中的�Q意一个字�W?范围)
[abc[hij]] a,b,c,h,i,j中的��L��一个字�W?�?span class="original_words">a|b|c|h|i|j相同)(�q��)
[a-z&&[hij]] h,i,j中的一�?交集)
\s �I�格字符(�I�格�? tab, 换行, 换页, 回�R)
\S 非空格字�W?[^\s])
\d 一个数字，也就�?span class="original_words">[0-9]
\D 一个非数字的字�W�，也就�?span class="original_words">[^0-9]
\w 一个单词字�W?word character)�Q�即[a-zA-Z_0-9]
\W 一个非单词的字�W�，[^\w]
如果你用�q�其它语�a�的正则表辑ּ��Q�那么你一眼就能看出反斜杠的与众不同。在其它语言里，"\\"的意思是"我只是要在正则表辑ּ�里插入一个反斜杠。没什么特别的意思�?但是在Java里，"\\"的意思是"我要插入一个正则表辑ּ�的反斜杠�Q�所以跟在它后面的那个字�W�的意思就变了�?举例来说�Q�如果你惌��C�Z��个或更多�?单词字符"�Q�那么这个正则表辑ּ��应该是"\\w+"。如果你要插入一个反斜杠�Q�那��得�?\\\\"。不�q�像换行�Q�蟩��g��cȝ��q�是只用一根反斜杠�Q?\n\t"�?/p>
�q�里只给你讲一个例子；你应�?span class="original_words">JDK文��?span class="original_words">java.util.regex.Pattern加到收藏多w��Q�这样就能很�Ҏ(gu��)��地找到各�U�正则表辑ּ�的模式了�?/p>
逻辑�q�算�W?
XY X 后面跟着 Y
X|Y X或Y
(X) 一�?要匹配的�l?capturing group)". 以后可以用\i来表�C�第i个被匚w��的组�?/td>
边界匚w��W?
^ 一行的开�?
$ 一行的�l�尾
\b 一个单词的边界
\B 一个非单词的边�?
\G 前一个匹配的�l�束
举一个具体一些的例子。下面这些正则表辑ּ�都是合法的，而且都能匚w��"Rudolph"�Q?/p>
Rudolph [rR]udolph [rR][aeiou][a-z]ol.* R.*
数量表示�W?/h3>
"数量表示�W?quantifier)"的作用是定义模式应该匚w��多少个字�W��?/p>
Greedy(贪婪�?�Q?除非另有表示�Q�否则数量表�C�符都是greedy的。Greedy的表辑ּ�会一直匹配下去，直到匚w��不下��Mؓ止�?u>(如果你发现表辑ּ�匚w��的结果与预期的不�W?�Q�很有可能是因�ؓ�Q�你以�ؓ表达式会只匹配前面几个字�W�，而实际上它是greedy的，因此会一直匹配下厅R�?
Reluctant(勉强�?�Q?用问可��C�，它会匚w��最��的字符。也�U�Cؓlazy, minimal matching, non-greedy, 或ungreedy�?
Possessive(占有�?�Q?目前只有Java支持(其它语言都不支持)。它更加先进�Q�所以你可能�q�不太会用。用正则表达式匹配字�W�串的时候会产生很多中间状态，(一般的匚w��引擎会保存这�U�中间状态，)�q�样匚w��p�|的时候就能原路返回了。占有型的表辑ּ�不保存这�U�中间状态，因此也就不会回头重来了。它能防止正则表辑ּ�的失控，同时也能提高�q�行的效率�?
Greedy Reluctant Possessive 匚w��
X? X?? X?+ 匚w��一个或零个X
X* X*? X*+ 匚w��零或多个X
X+ X+? X++ 匚w��一个或多个X
X{n} X{n}? X{n}+ 匚w��正好n�?span class="original_words">X
X{n,} X{n,}? X{n,}+ 匚w��臛_��n�?span class="original_words">X
X{n,m} X{n,m}? X{n,m}+ 匚w��臛_��n个，臛_��m�?span class="original_words">X
再提醒一下，要想让表辑ּ�照你的意思去�q�行�Q�你应该用括��h��'X'括�v来。比方说�Q?/p>
abc+
��g��q�个表达式能匚w��一个或若干�?abc'�Q�但是如果你真的用它��d��?abcabcabc'的话�Q�实际上只会扑ֈ�三个字符。因��个表辑ּ�的意思是'ab'后边跟着一个或多个'c'。要惛_��配一个或多个完整�?abc'�Q�你应该�q�样�Q?/p>
(abc)+
正则表达式能轻而易丑֜�把你�l�耍了�Q�这是一�U�徏立在Java之上的新语言�?/p>
CharSequence
JDK 1.4定义了一个新的接口，�?span class="original_words">CharSequence。它提供�?span class="original_words">String�?span class="original_words">StringBuffer�q�两个类的字�W�序列的抽象�Q?/p>
interface CharSequence { charAt(int i); length(); subSequence(int start, int end); toString(); }
��Z��实现�q�个新的CharSequence接口�Q?span class="original_words">String�Q?span class="original_words">StringBuffer以及CharBuffer都作了修攏V��很多正则表辑ּ�的操作都要拿CharSequence作参数�?/p>
Pattern�?span class="original_words">Matcher
先给一个例子。下面这�D늨�序可以测试正则表辑ּ�是否匚w��字符丌Ӏ�第一个参数是要匹配的字符�Ԍ��后面是正则表辑ּ�。正则表辑ּ�可以有多个。在Unix/Linux环境下，命��o行下的正则表辑ּ��q�必��ȝ��引号�?/p>
当你创徏正则表达式时�Q�可以用�q�个�E�序来判断它是不是会按照你的要求工作�?/p>
//: c12:TestRegularExpression.java// Allows you to easly try out regular expressions.// {Args: abcabcabcdefabc "abc+" "(abc)+" "(abc){2,}" }import java.util.regex.*; publicclass TestRegularExpression { publicstaticvoid main(String[] args) { if(args.length < 2) { System.out.println("Usage:\n" + "java TestRegularExpression " + "characterSequence regularExpression+"); System.exit(0); } System.out.println("Input: \"" + args[0] + "\""); for(int i = 1; i < args.length; i++) { System.out.println( "Regular expression: \"" + args[i] + "\""); Pattern p = Pattern.compile(args[i]); Matcher m = p.matcher(args[0]); while(m.find()) { System.out.println("Match \"" + m.group() + "\" at positions " + m.start() + "-" + (m.end() - 1)); } } } } ///:~
Java的正则表辑ּ�是由java.util.regex�?span class="original_words">Pattern�?span class="original_words">Matcher�c�d��现的�?span class="original_words">Pattern对象表示�l�编译的正则表达式。静态的compile( )�Ҏ(gu��)��负责��表�C�正则表辑ּ�的字�W�串�~�译�?span class="original_words">Pattern对象。正如上�q�C��E�所�C�的�Q�只要给Pattern�?span class="original_words">matcher( )�Ҏ(gu��)��送一个字�W�串��p��获取一�?span class="original_words">Matcher对象。此外，Pattern�q�有一个能快速判断能否在input里面扑ֈ�regex�?注意�Q�原文有误，漏了�Ҏ(gu��)��?
staticboolean matches( regex, input)
以及能返�?span class="original_words">String数组�?span class="original_words">split( )�Ҏ(gu��)��Q�它能用regex把字�W�串分割开来�?/p>
只要�l?span class="original_words">Pattern.matcher( )�Ҏ(gu��)��传一个字�W�串��p��获得Matcher对象了。接下来��p��?span class="original_words">Matcher的方法来查询匚w��的结果了�?/p>
boolean matches() boolean lookingAt() boolean find() boolean find(int start)
matches( )的前提是Pattern匚w��整个字符�Ԍ��?span class="original_words">lookingAt( )的意思是Pattern匚w��字符串的开头�?
find( )
Matcher.find( )的功能是发现CharSequence里的�Q�与pattern相匹配的多个字符序列。例如：
//: c12:FindDemo.javaimport java.util.regex.*; import com.bruceeckel.simpletest.*; import java.util.*; publicclass FindDemo { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) { Matcher m = Pattern.compile("\\w+") .matcher("Evening is full of the linnet's wings"); while(m.find()) System.out.println(m.group()); int i = 0; while(m.find(i)) { System.out.print(m.group() + " "); i++; } monitor.expect(new String[] { "Evening", "is", "full", "of", "the", "linnet", "s", "wings", "Evening vening ening ning ing ng g is is s full " + "full ull ll l of of f the the he e linnet linnet " + "innet nnet net et t s s wings wings ings ngs gs s " }); } } ///:~
"\\w+"的意思是"一个或多个单词字符"�Q�因此它会将字符串直接分解成单词�?span class="original_words">find( )像一个�P代器�Q�从头到��扫描一遍字�W�串。第二个find( )是带int参数的，正如你所看到的，它会告诉�Ҏ(gu��)��从哪里开始找——即从参��C��|�开始查找�?/p>
Groups
Group是指里用括号括�v来的�Q�能被后面的表达式调用的正则表达式。Group 0 表示整个表达式，group 1表示�W�一个被括�v来的group�Q�以此类推。所以；
A(B(C))D
里面有三个group�Q�group 0�?span class="original_words">ABCD�Q?group 1�?span class="original_words">BC�Q�group 2�?span class="original_words">C�?/p>
你可以用下述Matcher�Ҏ(gu��)��来��用group�Q?/p>
public int groupCount( )�q�回matcher对象中的group的数目。不包括group0�?/p>
public String group( ) �q�回上次匚w��操作(比方�?span class="original_words">find( ))的group 0(整个匚w��)
public String group(int i)�q�回上次匚w��操作的某个group。如果匹配成功，但是没能扑ֈ�group�Q�则�q�回null�?/p>
public int start(int group)�q�回上次匚w��所扑ֈ�的，group的开始位�|��?/p>
public int end(int group)�q�回上次匚w��所扑ֈ�的，group的结束位�|�，最后一个字�W�的下标加一�?/p>
下面我们举一些group的例子：
//: c12:Groups.javaimport java.util.regex.*; import com.bruceeckel.simpletest.*; publicclass Groups { privatestatic Test monitor = new Test(); staticpublicfinal String poem = "Twas brillig, and the slithy toves\n" + "Did gyre and gimble in the wabe.\n" + "All mimsy were the borogoves,\n" + "And the mome raths outgrabe.\n\n" + "Beware the Jabberwock, my son,\n" + "The jaws that bite, the claws that catch.\n" + "Beware the Jubjub bird, and shun\n" + "The frumious Bandersnatch."; publicstaticvoid main(String[] args) { Matcher m = Pattern.compile("(?m)(\\S+)\\s+((\\S+)\\s+(\\S+))$") .matcher(poem); while(m.find()) { for(int j = 0; j <= m.groupCount(); j++) System.out.print("[" + m.group(j) + "]"); System.out.println(); } monitor.expect(new String[]{ "[the slithy toves]" + "[the][slithy toves][slithy][toves]", "[in the wabe.][in][the wabe.][the][wabe.]", "[were the borogoves,]" + "[were][the borogoves,][the][borogoves,]", "[mome raths outgrabe.]" + "[mome][raths outgrabe.][raths][outgrabe.]", "[Jabberwock, my son,]" + "[Jabberwock,][my son,][my][son,]", "[claws that catch.]" + "[claws][that catch.][that][catch.]", "[bird, and shun][bird,][and shun][and][shun]", "[The frumious Bandersnatch.][The]" + "[frumious Bandersnatch.][frumious][Bandersnatch.]" }); } } ///:~
�q�首诗是Through the Looking Glass的，Lewis Carroll�?Jabberwocky"的第一部分。可以看到这个正则表辑ּ�里有很多用括��h��h��的group�Q�它是由��L��多个�q�箋的非�I�字�W?'\S+')和�Q意多个连�l�的�I�格字符('\s+')所�l�成的，其最�l�目的是要捕��h��行的最后三个单词；'$'表示一行的�l�尾。但�?$'通常表示整个字符串的�l�尾�Q�所以这里要明确地告诉正则表辑ּ�注意换行�W�。这一�Ҏ(gu��)��?(?m)'标志完成�?模式标志会过一会讲�?�?/p>
start( )和end( )
如果匚w��成功�Q?span class="original_words">start( )会返回此�ơ匹配的开始位�|�，end( )会返回此�ơ匹配的�l�束位置�Q�即最后一个字�W�的下标加一。如果之前的匚w��不成�?或者没匚w��)�Q�那么无论是调用start( )�q�是end( )�Q�都会引发一�?span class="original_words">IllegalStateException。下面这�D늨�序还演示�?span class="original_words">matches( )�?span class="original_words">lookingAt( )�Q?/p>
//: c12:StartEnd.javaimport java.util.regex.*; import com.bruceeckel.simpletest.*; publicclass StartEnd { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) { String[] input = new String[] { "Java has regular expressions in 1.4", "regular expressions now expressing in Java", "Java represses oracular expressions" }; Pattern p1 = Pattern.compile("re\\w*"), p2 = Pattern.compile("Java.*"); for(int i = 0; i < input.length; i++) { System.out.println("input " + i + ": " + input[i]); Matcher m1 = p1.matcher(input[i]), m2 = p2.matcher(input[i]); while(m1.find()) System.out.println("m1.find() '" + m1.group() + "' start = "+ m1.start() + " end = " + m1.end()); while(m2.find()) System.out.println("m2.find() '" + m2.group() + "' start = "+ m2.start() + " end = " + m2.end()); if(m1.lookingAt()) // No reset() necessary System.out.println("m1.lookingAt() start = " + m1.start() + " end = " + m1.end()); if(m2.lookingAt()) System.out.println("m2.lookingAt() start = " + m2.start() + " end = " + m2.end()); if(m1.matches()) // No reset() necessary System.out.println("m1.matches() start = " + m1.start() + " end = " + m1.end()); if(m2.matches()) System.out.println("m2.matches() start = " + m2.start() + " end = " + m2.end()); } monitor.expect(new String[] { "input 0: Java has regular expressions in 1.4", "m1.find() 'regular' start = 9 end = 16", "m1.find() 'ressions' start = 20 end = 28", "m2.find() 'Java has regular expressions in 1.4'" + " start = 0 end = 35", "m2.lookingAt() start = 0 end = 35", "m2.matches() start = 0 end = 35", "input 1: regular expressions now " + "expressing in Java", "m1.find() 'regular' start = 0 end = 7", "m1.find() 'ressions' start = 11 end = 19", "m1.find() 'ressing' start = 27 end = 34", "m2.find() 'Java' start = 38 end = 42", "m1.lookingAt() start = 0 end = 7", "input 2: Java represses oracular expressions", "m1.find() 'represses' start = 5 end = 14", "m1.find() 'ressions' start = 27 end = 35", "m2.find() 'Java represses oracular expressions' " + "start = 0 end = 35", "m2.lookingAt() start = 0 end = 35", "m2.matches() start = 0 end = 35" }); } } ///:~
注意�Q�只要字�W�串里有�q�个模式�Q?span class="original_words">find( )��p��把它�l�找出来�Q�但�?span class="original_words">lookingAt( )�?span class="original_words">matches( )�Q�只有在字符串与正则表达式一开始就相匹配的情况下才能返�?span class="original_words">true�?span class="original_words">matches( )成功的前提是正则表达式与字符串完全匹配，�?span class="original_words">lookingAt( )^[67]成功的前提是�Q�字�W�串的开始部分与正则表达式相匚w��?/p>
匚w��的模�?Pattern flags)
compile( )�Ҏ(gu��)��q�有一个版本，它需要一个控制正则表辑ּ�的匹配行为的参数�Q?/p>
Pattern Pattern.compile(String regex, int flag)
flag的取��D��围如下：
�~�译标志效果
Pattern.CANON_EQ 当且仅当两个字符�?正规分解(canonical decomposition)"都完全相同的情况下，才认定匹配。比如用了这个标志之后，表达�?a\u030A"会匹�??"。默认情况下�Q�不考虑"规范相等�?canonical equivalence)"�?
Pattern.CASE_INSENSITIVE
(?i) 默认情况下，大小写不明感的匹配只适用于US-ASCII字符集。这个标志能让表辑ּ�忽略大小写进行匹配。要惛_��Unicode字符�q�行大小不明感的匚w��Q�只要将UNICODE_CASE与这个标志合��h��p��了�?
Pattern.COMMENTS
(?x) 在这�U�模式下�Q�匹配时会忽�?正则表达式里�?�I�格字符(译者注�Q�不是指表达式里�?\\s"�Q�而是指表辑ּ�里的�I�格�Q�tab�Q�回车之�c?。注释从#开始，一直到�q�行�l�束。可以通过嵌入式的标志来启用Unix行模式�?
Pattern.DOTALL
(?s) 在这�U�模式下�Q�表辑ּ�'.'可以匚w��L��字符�Q�包括表�C�Z��行的�l�束�W�。默认情况下�Q�表辑ּ�'.'不匹配行的结束符�?
Pattern.MULTILINE
(?m) 在这�U�模式下�Q?^'�?$'分别匚w��一行的开始和�l�束。此外，'^'仍然匚w��字符串的开始，'$'也匹配字�W�串的结束。默认情况下�Q�这两个表达式仅仅匹配字�W�串的开始和�l�束�?
Pattern.UNICODE_CASE
(?u) 在这个模式下�Q�如果你�q�启用了CASE_INSENSITIVE标志�Q�那么它会对Unicode字符�q�行大小写不明感的匹配。默认情况下�Q�大��写不明感的匚w��只适用于US-ASCII字符集�?
Pattern.UNIX_LINES
(?d) 在这个模式下�Q�只�?\n'才被认作一行的中止�Q��ƈ且与'.'�Q?^'�Q�以�?$'�q�行匚w��?
在这些标志里面，Pattern.CASE_INSENSITIVE�Q?span class="original_words">Pattern.MULTILINE�Q�以�?span class="original_words">Pattern.COMMENTS是最有用�?其中Pattern.COMMENTS�q�能帮我们把思�\理清楚，�q�且/或者做文档)。注意，你可以用在表辑ּ�里插记号的方式来启用�l�大多数的模式。这些记号就在上面那张表的各个标志的下面。你希望模式从哪里开始启动，��在哪里插记受��?/p>
可以�?OR" ('|')�q�算�W�把�q�些标志合��用：
//: c12:ReFlags.javaimport java.util.regex.*; import com.bruceeckel.simpletest.*; publicclass ReFlags { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) { Pattern p = Pattern.compile("^java", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE); Matcher m = p.matcher( "java has regex\nJava has regex\n" + "J***A has pretty good regular expressions\n" + "Regular expressions are in Java"); while(m.find()) System.out.println(m.group()); monitor.expect(new String[] { "java", "Java", "J***A" }); } } ///:~
�q�样创徏出来的正则表辑ּ��p��匚w��?java"�Q?Java"�Q?J***A"...开头的字符串了。此外，如果字符串分好几行，那它�q�会�Ҏ(gu��)��一行做匚w��(匚w��始于字符序列的开始，�l�于字符序列当中的行�l�束�W?。注意，group( )�Ҏ(gu��)��仅返回匹配的部分�?/p>
split( )
所谓分割是指将以正则表辑ּ�为界�Q�将字符串分割成String数组�?/p>
String[] split(CharSequence charseq) String[] split(CharSequence charseq, int limit)
�q�是一�U�既快又方便地将文本�Ҏ(gu��)��一些常见的边界标志分割开来的�Ҏ(gu��)��?/p>
//: c12:SplitDemo.javaimport java.util.regex.*; import com.bruceeckel.simpletest.*; import java.util.*; publicclass SplitDemo { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) { String input = "This!!unusual use!!of exclamation!!points"; System.out.println(Arrays.asList( Pattern.compile("!!").split(input))); // Only do the first three: System.out.println(Arrays.asList( Pattern.compile("!!").split(input, 3))); System.out.println(Arrays.asList( "Aha! String has a split() built in!".split(" "))); monitor.expect(new String[] { "[This, unusual use, of exclamation, points]", "[This, unusual use, of exclamation!!points]", "[Aha!, String, has, a, split(), built, in!]" }); } } ///:~
�W�二�?span class="original_words">split( )会限定分割的�ơ数�?/p>
正则表达式是如此重要�Q�以至于有些功能被加�q�了String�c�，其中包括split( )(已经看到�?�Q?span class="original_words">matches( )�Q?span class="original_words">replaceFirst( )以及replaceAll( )。这些方法的功能�?span class="original_words">Pattern�?span class="original_words">Matcher的相同�?
替换操作
正则表达式在替换文本斚w��特别在行。下面就是一些方法：
replaceFirst(String replacement)��字�W�串里，�W�一个与模式相匹配的子串替换�?span class="original_words">replacement�?
replaceAll(String replacement)�Q�将输入字符串里所有与模式相匹配的子串全部替换�?span class="original_words">replacement�?/p>
appendReplacement(StringBuffer sbuf, String replacement)�?span class="original_words">sbuf�q�行逐次替换�Q�而不是像replaceFirst( )�?span class="original_words">replaceAll( )那样�Q�只替换�W�一个或全部子串。这是个非常重要的方法，因�ؓ它可以调用方法来生成replacement(replaceFirst( )�?span class="original_words">replaceAll( )只允许用固定的字�W�串来充�?span class="original_words">replacement)。有了这个方法，你就可以�~�程区分group�Q�从而实现更强大的替换功能�?/p>
调用�?span class="original_words">appendReplacement( )之后�Q��ؓ了把剩余的字�W�串拯��回去�Q�必��调�?span class="original_words">appendTail(StringBuffer sbuf, String replacement)�?
下面我们来演�C�Z��下怎样使用�q�些替换�Ҏ(gu��)��。说明一下，�q�段�E�序所处理的字�W�串是它自己开头部分的注释�Q�是用正则表辑ּ�提取出来�q�加以处理之后再传给替换�Ҏ(gu��)��的�?/p>
//: c12:TheReplacements.javaimport java.util.regex.*; import java.io.*; import com.bruceeckel.util.*; import com.bruceeckel.simpletest.*; /*! Here's a block of text to use as input to the regular expression matcher. Note that we'll first extract the block of text by looking for the special delimiters, then process the extracted block. !*/publicclass TheReplacements { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) throws Exception { String s = TextFile.read("TheReplacements.java"); // Match the specially-commented block of text above: Matcher mInput = Pattern.compile("/\\*!(.*)!\\*/", Pattern.DOTALL) .matcher(s); if(mInput.find()) s = mInput.group(1); // Captured by parentheses// Replace two or more spaces with a single space: s = s.replaceAll(" {2,}", " "); // Replace one or more spaces at the beginning of each// line with no spaces. Must enable MULTILINE mode: s = s.replaceAll("(?m)^ +", ""); System.out.println(s); s = s.replaceFirst("[aeiou]", "(VOWEL1)"); StringBuffer sbuf = new StringBuffer(); Pattern p = Pattern.compile("[aeiou]"); Matcher m = p.matcher(s); // Process the find information as you// perform the replacements:while(m.find()) m.appendReplacement(sbuf, m.group().toUpperCase()); // Put in the remainder of the text: m.appendTail(sbuf); System.out.println(sbuf); monitor.expect(new String[]{ "Here's a block of text to use as input to", "the regular expression matcher. Note that we'll", "first extract the block of text by looking for", "the special delimiters, then process the", "extracted block. ", "H(VOWEL1)rE's A blOck Of tExt tO UsE As InpUt tO", "thE rEgUlAr ExprEssIOn mAtchEr. NOtE thAt wE'll", "fIrst ExtrAct thE blOck Of tExt by lOOkIng fOr", "thE spEcIAl dElImItErs, thEn prOcEss thE", "ExtrActEd blOck. " }); } } ///:~
我们用前面介�l�的TextFile.read( )�Ҏ(gu��)��来打开和读取文件�?span class="original_words">mInput的功能是匚w��'/*!' �?'!*/' 之间的文�?注意一下分�l�用的括�?。接下来�Q�我们将所有两个以上的�q�箋�I�格全都替换成一个，�q�且��各行开头的�I�格全都��L��(��Z��让这个正则表辑ּ�能对所有的行，而不仅仅是第一行�v作用�Q�必��d��用多行模�?。这两个操作都用�?span class="original_words">String�?span class="original_words">replaceAll( )(�q�里用它更方�?。注意，�׃��每个替换只做一�ơ，因此除了预编�?span class="original_words">Pattern之外�Q�程序没有额外的开销�?/p>
replaceFirst( )只替换第一个子丌Ӏ�此外，replaceFirst( )�?span class="original_words">replaceAll( )只能用常�?literal)来替换，所以如果你每次替换的时候还要进行一些操作的话，它们是无能�ؓ力的。碰到这�U�情况，你得�?span class="original_words">appendReplacement( )�Q�它能让你在�q�行替换的时候想写多��代码就写多��。在上面那段�E�序里，创徏sbuf的过�E�就是选group做处理，也就是用正则表达式把元音字母扑և�来，然后换成大写的过�E�。通常你得在完成全部的替换之后才调�?span class="original_words">appendTail( )�Q�但是如果要模仿replaceFirst( )(�?replace n")的效果，你也可以只替换一�ơ就调用appendTail( )。它会把剩下的东西全都放�q?span class="original_words">sbuf�?/p>
你还可以�?span class="original_words">appendReplacement( )�?span class="original_words">replacement参数里用"$g"引用已捕��L(f��ng)��group�Q�其�?g' 表示group的号码。不�q�这是�ؓ一些比较简单的操作准备的，因而其效果无法与上�q�程序相比�?/p>
reset( )
此外�Q�还可以�?span class="original_words">reset( )�Ҏ(gu��)��l�现有的Matcher对象配上个新�?span class="original_words">CharSequence�?/p>
//: c12:Resetting.javaimport java.util.regex.*; import java.io.*; import com.bruceeckel.simpletest.*; publicclass Resetting { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) throws Exception { Matcher m = Pattern.compile("[frb][aiu][gx]") .matcher("fix the rug with bags"); while(m.find()) System.out.println(m.group()); m.reset("fix the rig with rags"); while(m.find()) System.out.println(m.group()); monitor.expect(new String[]{ "fix", "rug", "bag", "fix", "rig", "rag" }); } } ///:~
如果不给参数�Q?span class="original_words">reset( )会把Matcher讑ֈ�当前字符串的开始处�?/p>
正则表达式与Java I/O
到目前�ؓ止，你看到的都是用正则表辑ּ�处理静态字�W�串的例子。下面我们来演示一下怎样用正则表辑ּ�扫描文�g�q�且扑և�匚w��的字�W�串。受Unix的grep启发�Q�我写了�?span class="original_words">JGrep.java�Q�它需要两个参敎ͼ�文�g名，以及匚w��字符串用的正则表辑ּ�。它会把匚w��q�个正则表达式那部分内容及其所属行的行��h��印出来�?/p>
//: c12:JGrep.java// A very simple version of the "grep" program.// {Args: JGrep.java "\\b[Ssct]\\w+"}import java.io.*; import java.util.regex.*; import java.util.*; import com.bruceeckel.util.*; publicclass JGrep { publicstaticvoid main(String[] args) throws Exception { if(args.length < 2) { System.out.println("Usage: java JGrep file regex"); System.exit(0); } Pattern p = Pattern.compile(args[1]); // Iterate through the lines of the input file: ListIterator it = new TextFile(args[0]).listIterator(); while(it.hasNext()) { Matcher m = p.matcher((String)it.next()); while(m.find()) System.out.println(it.nextIndex() + ": " + m.group() + ": " + m.start()); } } } ///:~
文�g是用TextFile打开�?本章的前半部分讲�?。由�?span class="original_words">TextFile会把文�g的各行放�?span class="original_words">ArrayList里面�Q�而我们又提取了一�?span class="original_words">ListIterator�Q�因此我们可以在文�g的各行当中自��q��?既能向前也可以向�?�?
每行都会有一�?span class="original_words">Matcher�Q�然后用find( )扫描。注意，我们�?span class="original_words">ListIterator.nextIndex( )跟踪行号�?
��试参数�?span class="original_words">JGrep.java和以[Ssct]开头的单词�?/p>
�q�需要StringTokenizer�?
看到正则表达式能提供�q�么强大的功能，你可能会怀疑，是不是还需要原先的StringTokenizer。JDK 1.4以前�Q�要惛_��割字�W�串�Q�只有用StringTokenizer。但现在�Q�有了正则表辑ּ�之后�Q�它?y��u)��p��做得更干净利烦了�?/p>
//: c12:ReplacingStringTokenizer.javaimport java.util.regex.*; import com.bruceeckel.simpletest.*; import java.util.*; publicclass ReplacingStringTokenizer { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) { String input = "But I'm not dead yet! I feel happy!"; StringTokenizer stoke = new StringTokenizer(input); while(stoke.hasMoreElements()) System.out.println(stoke.nextToken()); System.out.println(Arrays.asList(input.split(" "))); monitor.expect(new String[] { "But", "I'm", "not", "dead", "yet!", "I", "feel", "happy!", "[But, I'm, not, dead, yet!, I, feel, happy!]" }); } } ///:~
有了正则表达式，你就能用更复杂的模式��字�W�串分割开来——要是交�l?span class="original_words">StringTokenizer的话�Q�事情会�ȝ��得多。我可以很有把握地说�Q�正则表辑ּ�可以取代StringTokenizer�?
要想�q�一步学�?f��n)正则表辑ּ��Q�徏议你�?cite>Mastering Regular Expression, 2nd Edition�Q�作者Jeffrey E. F. Friedl (O’Reilly, 2002)�?/p>
�ȝ��
Java的I/O��类库应该能满��你的基本需求：你可以用它来��d��控制収ͼ�文�g�Q�内存，甚至是Internet。你�q�可以利用��承来创徏新的输入和输出类型。你甚至可以利用Java会自动调用对象的toString( )�Ҏ(gu��)��的特�?Java仅有�?自动�c�d��转换")�Q�通过重新定义�q�个�Ҏ(gu��)��Q�来对要传给��的对象做一个简单的扩展�?/p>
但是Java的I/O��类库及其文��还是留下了一些缺憾。比方说你打开一个文件往里面写东西，但是�q�个文�g已经有了�Q�这么做会把原先的内容给覆盖�?。这时要是能有一个异常就好了——有些编�E�语�a�能让你规定只能往新徏的文仉��输出。看来Java是要你用File对象来判断文件是否存在，因�ؓ如果你用FileOutputStream�?span class="original_words">FileWriter的话�Q�文件就会被覆盖了�?/p>
我对I/O��类库的评�h(hu��n)是比较矛盄��Q�它��实能干很多事情�Q�而且做到了跨�q�_��。但是如果你不懂decorator模式�Q�就会觉得这�U�设计太隄��解了�Q�所以无论是对老师�q�是学生�Q�都得多��q��力。此外这个类库也不完��_��否则我也用不着��d��TextFile了。此外它没有提供格式化输出的功能�Q�而其他语�a�都已�l�提供了�q�种功能�?/p>

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resolution to "Can't rollforward due to large bufferpool size "

about DB2 Administration (refer from others)

Using DB2 Configuration Assistance

Using DB2 CLP and CE

Problem Description

Check Process

Cause

Solution

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Reference

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REORG TABLE

DB2 存储�q�程问题(�?

CharSequence

Pattern�?span class="original_words">Matcher

find( )

Groups

start( )和end( )

匚w��的模�?Pattern flags)

split( )

替换操作

reset( )

正则表达式与Java I/O

�q�需要StringTokenizer�?

�ȝ��

三个UNIX文�g旉��ctime、mtime、atime