DB2相关数据库命令

1.数据库实例的启动
首先要启动数据库的实例,即切换到db2inst1用户(注:db2inst1用户为当前数据库的实例),然后执行db2start启动数据库的实例
[root@localhost instance]# su - db2inst1
[db2inst1@localhost ~]$ db2start
SQL1063N  DB2START processing was successful.
[db2inst1@localhost ~]$

2.数据库实例的关闭
首先在db2inst1用户下强制关闭实例上的所有应用程序,然后再关闭数据库实例
[db2inst1@localhost ~]$ db2 force application all
DB20000I  The FORCE APPLICATION command completed successfully.
DB21024I  This command is asynchronous and may not be effective immediately.

[db2inst1@localhost ~]$ db2stop
SQL1064N  DB2STOP processing was successful.
[db2inst1@localhost ~]$

强制停止
[db2inst1@localhost DB2]$ db2stop force
SQL1064N  DB2STOP processing was successful.
[db2inst1@localhost DB2]$

3.显示所有的实例
[db2inst1@localhost ~]$ db2ilist
db2inst1
[db2inst1@localhost ~]$

4.显示当前的实例
[db2inst1@localhost ~]$ db2 get instance

 The current database manager instance is:  db2inst1

[db2inst1@localhost ~]$

5.删除一个实例(注:需切换到root用户权限下)
[root@localhost ~]# cd /opt/ibm/db2/V9.7/instance
[root@localhost instance]# pwd
/opt/ibm/db2/V9.7/instance
[root@localhost instance]# ./db2idrop db2inst1
DBI1070I  Program db2idrop completed successfully.

[root@localhost instance]#

6.列出当前实例中有哪些数据库
[root@localhost instance]# su - db2inst1
[db2inst1@localhost ~]$ db2 list db directory
SQL1031N  The database directory cannot be found on the indicated file system.

SQLSTATE=58031
[db2inst1@localhost ~]$
注:上面信息说明实例中没有数据库

7.创建数据库
[root@localhost instance]# su - db2inst1
[db2inst1@localhost ~]$ db2 create database test
SQL1032N  No start database manager command was issued.  SQLSTATE=57019
[db2inst1@localhost ~]$
[db2inst1@localhost ~]$ db2start
SQL5043N  Support for one or more communications protocols failed to start successfully. However, core database manager functionality started successfully.
[db2inst1@localhost ~]$ db2 create database test
DB20000I  The CREATE DATABASE command completed successfully.
[db2inst1@localhost ~]$ db2 list db directory

 System Database Directory

 Number of entries in the directory = 1

Database 1 entry:

 Database alias                       = TEST
 Database name                        = TEST
 Local database directory             = /home/db2inst1
 Database release level               = d.00
 Comment                              =
 Directory entry type                 = Indirect
 Catalog database partition number    = 0
 Alternate server hostname            =
 Alternate server port number         =

[db2inst1@localhost ~]$
注:上面通过创建一个test的数据库,并说明了创建数据库时,要先启动数据库,然后创建数据库test成功后并列出了当前实例中的所有数据库,只存在数据库test

使用UTF-8编码 
db2 create database test on '/home/db2inst1' using codeset UTF-8 territory CN
on '/home/db2inst1' 表示数据库路径
一般情况下'/home/db2inst1'为默认数据库路径

8.连接数据库
[db2inst1@localhost ~]$ db2 connect to test

   Database Connection Information

 Database server        = DB2/LINUX 9.7.1
 SQL authorization ID   = DB2INST1
 Local database alias   = TEST

[db2inst1@localhost ~]$

注:用密码情况下格式[db2inst1@localhost ~]$ db2 connect to test user username using password

db2 connect to <database> user <username> using  <password>

9.列出当前实例中所有激活的数据库
[root@localhost ~]# su - db2inst1
[db2inst1@localhost ~]$ db2 list active databases
SQL1032N  No start database manager command was issued.  SQLSTATE=57019
[db2inst1@localhost ~]$ db2 list db directory

 System Database Directory

 Number of entries in the directory = 1

Database 1 entry:

 Database alias                       = TEST
 Database name                        = TEST
 Local database directory             = /home/db2inst1
 Database release level               = d.00
 Comment                              =
 Directory entry type                 = Indirect
 Catalog database partition number    = 0
 Alternate server hostname            =
 Alternate server port number         =

[db2inst1@localhost ~]$ db2start
SQL1026N  The database manager is already active.
[db2inst1@localhost ~]$ db2 list active databases
SQL1611W  No data was returned by Database System Monitor.
[db2inst1@localhost ~]$ db2 connect to test

   Database Connection Information

 Database server        = DB2/LINUX 9.7.1
 SQL authorization ID   = DB2INST1
 Local database alias   = TEST

[db2inst1@localhost ~]$ db2 list active databases

                           Active Databases

Database name                              = TEST
Applications connected currently           = 1
Database path                              = /home/db2inst1/db2inst1/NODE0000/SQL00001/

[db2inst1@localhost ~]$
注:可以看出查看当前激活的数据库为已经启动后连接的数据库

10.查看表的空间
[db2inst1@localhost ~]$ db2 list tablespaces [ show detail ]

           Tablespaces for Current Database

 Tablespace ID                        = 0
 Name                                 = SYSCATSPACE
 Type                                 = Database managed space
 Contents                             = All permanent data. Regular table space.
 State                                = 0x0000
   Detailed explanation:
     Normal

 Tablespace ID                        = 1
 Name                                 = TEMPSPACE1
 Type                                 = System managed space
 Contents                             = System Temporary data
 State                                = 0x0000
   Detailed explanation:
     Normal

 Tablespace ID                        = 2
 Name                                 = USERSPACE1
 Type                                 = Database managed space
 Contents                             = All permanent data. Large table space.
 State                                = 0x0000
   Detailed explanation:
     Normal

[db2inst1@localhost ~]$
注: show detail为可选项,显示更详细信息

或者 db2pd -tablespaces -db 数据库名
[db2inst1@localhost ~]$ db2pd -tablespaces -db test

Database Partition 0 -- Database TEST -- Active -- Up 0 days 00:03:11

Tablespace Configuration:
Address    Id    Type Content PageSz ExtentSz Auto Prefetch BufID BufIDDisk FSC NumCntrs MaxStripe  LastConsecPg Name
0x9DC2A060 0     DMS  Regular 4096   4        Yes  4        1     1         Off 1        0          3            SYSCATSPACE
0x9DC2B4B0 1     SMS  SysTmp  4096   32       Yes  32       1     1         On  1        0          31           TEMPSPACE1
0x9DC30940 2     DMS  Large   4096   32       Yes  32       1     1         Off 1        0          31           USERSPACE1

Tablespace Statistics:
Address    Id    TotalPgs   UsablePgs  UsedPgs    PndFreePgs FreePgs    HWM        Max HWM    State      MinRecTime NQuiescers PathsDropped
0x9DC2A060 0     24576      24572      18712      0          5860       18712      18712      0x00000000 0          0          No         
0x9DC2B4B0 1     1          1          1          0          0          0          0          0x00000000 0          0          No         
0x9DC30940 2     8192       8160       96         0          8064       96         96         0x00000000 0          0          No         

Tablespace Autoresize Statistics:
Address    Id    AS  AR  InitSize    IncSize     IIP MaxSize     LastResize                 LRF
0x9DC2A060 0     Yes Yes 33554432    -1          No  None        None                       No 
0x9DC2B4B0 1     Yes No  0           0           No  0                    None                       No 
0x9DC30940 2     Yes Yes 33554432    -1          No  None        None                       No 

Containers:
Address    TspId ContainNum Type    TotalPgs   UseablePgs PathID     StripeSet  Container
0x9B218F00 0     0          File    24576      24572      0          0          /home/db2inst1/db2inst1/NODE0000/TEST/T0000000/C0000000.CAT
0x9B219120 1     0          Path    1          1          0          0          /home/db2inst1/db2inst1/NODE0000/TEST/T0000001/C0000000.TMP
0x9B219390 2     0          File    8192       8160       0          0          /home/db2inst1/db2inst1/NODE0000/TEST/T0000002/C0000000.LRG
[db2inst1@localhost ~]$

11.列出数据库中所有用户表
[db2inst1@localhost ~]$ db2 connect to test

   Database Connection Information

 Database server        = DB2/LINUX 9.7.1
 SQL authorization ID   = DB2INST1
 Local database alias   = TEST

[db2inst1@localhost ~]$  db2 list tables

Table/View                      Schema          Type  Creation time            
------------------------------- --------------- ----- --------------------------

  0 record(s) selected.

[db2inst1@localhost ~]$

注:上面信息说明数据库test中还没有表

12.在数据库test中创建表student
[db2inst1@localhost ~]$ db2 connect to test

   Database Connection Information

 Database server        = DB2/LINUX 9.7.1
 SQL authorization ID   = DB2INST1
 Local database alias   = TEST

[db2inst1@localhost ~]$ db2 "create table student (id int,fname varchar(30),age int)"
DB20000I  The SQL command completed successfully.
[db2inst1@localhost ~]$ db2 list tables

Table/View                      Schema          Type  Creation time            
------------------------------- --------------- ----- --------------------------
STUDENT                         DB2INST1        T     2012-08-06-14.38.33.456768

  1 record(s) selected.

[db2inst1@localhost ~]$

13.向表student中添加数据信息
[db2inst1@localhost ~]$ db2 "insert into student values (1,'Tom',22)"
DB20000I  The SQL command completed successfully.
[db2inst1@localhost ~]$ db2 "insert into student values (2,'Jack',21)"
DB20000I  The SQL command completed successfully.
[db2inst1@localhost ~]$ db2 "insert into student values (3,'Sunrier',25)"
DB20000I  The SQL command completed successfully.
[db2inst1@localhost ~]$

14.显示表student所有的信息
[db2inst1@localhost ~]$ db2 "select * from student"

ID          FNAME                          AGE       
----------- ------------------------------ -----------
          1 Tom                                     22
          2 Jack                                    21
          3 Sunrier                                 25

  3 record(s) selected.

[db2inst1@localhost ~]$

15.更改表student中的数据(如将Sunrier的年龄改为22)
[db2inst1@localhost ~]$ db2 "select * from student"

ID          FNAME                          AGE       
----------- ------------------------------ -----------
          1 Tom                                     22
          2 Jack                                    21
          3 Sunrier                                 25

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 "update student set age=22 where fname='Sunrier'"
DB20000I  The SQL command completed successfully.
[db2inst1@localhost ~]$ db2 "select * from student"

ID          FNAME                          AGE       
----------- ------------------------------ -----------
          1 Tom                                     22
          2 Jack                                    21
          3 Sunrier                                 22

  3 record(s) selected.

[db2inst1@localhost ~]$

16.查看表student结构

[db2inst1@localhost ~]$ db2 describe table student

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
ID                              SYSIBM    INTEGER                      4     0 Yes  
FNAME                           SYSIBM    VARCHAR                     30     0 Yes  
AGE                             SYSIBM    INTEGER                      4     0 Yes  

  3 record(s) selected.

[db2inst1@localhost ~]$

或
[db2inst1@localhost ~]$ db2 "describe select * from student"

 Column Information

 Number of columns: 3

 SQL type              Type length  Column name                     Name length
 --------------------  -----------  ------------------------------  -----------
 497   INTEGER                   4  ID                                        2
 449   VARCHAR                  30  FNAME                                     5
 497   INTEGER                   4  AGE                                       3

[db2inst1@localhost ~]$

或
[db2inst1@localhost ~]$ db2 "describe select * from db2inst1.student"

 Column Information

 Number of columns: 3

 SQL type              Type length  Column name                     Name length
 --------------------  -----------  ------------------------------  -----------
 497   INTEGER                   4  ID                                        2
 449   VARCHAR                  30  FNAME                                     5
 497   INTEGER                   4  AGE                                       3

[db2inst1@localhost ~]$

17.创建一个新表(如people)与数据库中某个表(如student)结构相同
[db2inst1@localhost ~]$ db2 list tables

Table/View                      Schema          Type  Creation time            
------------------------------- --------------- ----- --------------------------
STUDENT                         DB2INST1        T     2012-08-06-15.26.17.189538

  1 record(s) selected.
 
[db2inst1@localhost ~]$ db2 describe table student

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
ID                              SYSIBM    INTEGER                      4     0 Yes  
FNAME                           SYSIBM    VARCHAR                     30     0 Yes  
AGE                             SYSIBM    INTEGER                      4     0 Yes  

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 "select * from student"

ID          FNAME                          AGE       
----------- ------------------------------ -----------
          1 Tom                                     22
          2 Jack                                    21
          3 Sunrier                                 25

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 create table people like student
DB20000I  The SQL command completed successfully.
[db2inst1@localhost ~]$ db2 list tables

Table/View                      Schema          Type  Creation time            
------------------------------- --------------- ----- --------------------------
PEOPLE                          DB2INST1        T     2012-08-16-15.13.49.396370
STUDENT                         DB2INST1        T     2012-08-06-15.26.17.189538

  2 record(s) selected.

[db2inst1@localhost ~]$ db2 describe table people

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
ID                              SYSIBM    INTEGER                      4     0 Yes  
FNAME                           SYSIBM    VARCHAR                     30     0 Yes  
AGE                             SYSIBM    INTEGER                      4     0 Yes  

  3 record(s) selected.

[db2inst1@localhost ~]$

18.两个结构相同的表,将原来数据库中某个表(如student)的数据导入与它相同结构的新表(如people)中
[db2inst1@localhost ~]$ db2 list tables

Table/View                      Schema          Type  Creation time            
------------------------------- --------------- ----- --------------------------
PEOPLE                          DB2INST1        T     2012-08-16-15.13.49.396370
STUDENT                         DB2INST1        T     2012-08-06-15.26.17.189538

  2 record(s) selected.

[db2inst1@localhost ~]$ db2 describe table student

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
ID                              SYSIBM    INTEGER                      4     0 Yes  
FNAME                           SYSIBM    VARCHAR                     30     0 Yes  
AGE                             SYSIBM    INTEGER                      4     0 Yes  

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 describe table people

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
ID                              SYSIBM    INTEGER                      4     0 Yes  
FNAME                           SYSIBM    VARCHAR                     30     0 Yes  
AGE                             SYSIBM    INTEGER                      4     0 Yes  

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 "select * from student"

ID          FNAME                          AGE       
----------- ------------------------------ -----------
          1 Tom                                     22
          2 Jack                                    21
          3 Sunrier                                 25

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 "select * from people"

ID          FNAME                          AGE       
----------- ------------------------------ -----------

  0 record(s) selected.
 
[db2inst1@localhost ~]$ db2 "insert into people select * from student"
DB20000I  The SQL command completed successfully.
[db2inst1@localhost ~]$ db2 "select * from people"

ID          FNAME                          AGE       
----------- ------------------------------ -----------
          1 Tom                                     22
          2 Jack                                    21
          3 Sunrier                                 25

  3 record(s) selected.

[db2inst1@localhost ~]$

19.修改一个表的字段类型(如表people中的fname字段把varchar(30)改为varchar(28))
[db2inst1@localhost ~]$ db2 describe table people

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
ID                              SYSIBM    INTEGER                      4     0 Yes  
FNAME                           SYSIBM    VARCHAR                     30     0 Yes  
AGE                             SYSIBM    INTEGER                      4     0 Yes  

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 "select * from people"

ID          FNAME                          AGE       
----------- ------------------------------ -----------
          1 Tom                                     22
          2 Jack                                    21
          3 Sunrier                                 25

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 "alter table people alter column fname set data type varchar(28)"
DB20000I  The SQL command completed successfully.
[db2inst1@localhost ~]$ db2 describe table people

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
ID                              SYSIBM    INTEGER                      4     0 Yes  
FNAME                           SYSIBM    VARCHAR                     28     0 Yes  
AGE                             SYSIBM    INTEGER                      4     0 Yes  

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 "select * from people"

ID          FNAME                        AGE       
----------- ---------------------------- -----------
          1 Tom                                   22
          2 Jack                                  21
          3 Sunrier                               25

  3 record(s) selected.

[db2inst1@localhost ~]$

格式:db2 "alter table <tablename> alter column <columnname> set data type <datatype>"
tablename:表名
columnname:字段名
datatype:字段类型

注:
一般更改字段类型是有操作限制的. 将字段改为比之前类型长度大的可以;如果要改小,必须先drop掉原来的column,然后再重新添加.
虽然我上面的执行成功了,可能是因为我用的官方免费版本的,如果遇到把长度大的改为小的无法执行,先用drop,再重新添加

20.向一个表添加字段(如向表people中添加备注信息字段notes;向表people中添加分数字段score)
格式:db2 "alter table <tablename> add <columnname> <datatype>"
[db2inst1@localhost ~]$ db2 describe table people

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
ID                              SYSIBM    INTEGER                      4     0 Yes  
FNAME                           SYSIBM    VARCHAR                     30     0 Yes  
AGE                             SYSIBM    INTEGER                      4     0 Yes  

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 "select * from people"

ID          FNAME                          AGE       
----------- ------------------------------ -----------
          1 Tom                                     22
          2 Jack                                    21
          3 Sunrier                                 25

  3 record(s) selected.

[db2inst1@localhost ~]$ db2 "alter table people add notes varchar(100)"
DB20000I  The SQL command completed successfully.
[db2inst1@localhost ~]$ db2 describe table people

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
ID                              SYSIBM    INTEGER                      4     0 Yes  
FNAME                           SYSIBM    VARCHAR                     36     0 Yes  
AGE                             SYSIBM    INTEGER                      4     0 Yes  
NOTES                           SYSIBM    VARCHAR                    100     0 Yes  

  4 record(s) selected.

[db2inst1@localhost ~]$ db2 "select * from people"

ID          FNAME                                AGE         NOTES                                                                                              
----------- ------------------------------------ ----------- ----------------------------------------------------------------------------------------------------
          1 Tom                                           22 -