DB2命令
一、常用命令
1、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、连接数据库
connect to sample1 user db2admin using 8301206
3、建立用户、建立表别名
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;
GRANT DBADM,CREATETAB,BINDADD,CONNECT,CREATE_NOT_FENCED_ROUTINE ON DATABASE TO USER GUEST;
GRANT CREATEIN,DROPIN,ALTERIN ON SCHEMA DB2ADMIN TO USER GUEST WITH GRANT OPTION;
4、建立、更改、删除表结构
CREATE TABLE table_name(
column1 DATATYPE [NOT NULL] [NOT NULL PRIMARY KEY],
column2 DATATYPE [NOT NULL],
...)
create table zjt_tables as
(select * from tables) definition only;
create table zjt_views as
(select * from views) definition only;
ALTER TABLE table_name ADD COLUMN column_name DATATYPE
ALTER TABLE table_name ADD PRIMARY KEY (column_name)
ALTER TABLE table_name DROP PRIMARY KEY (column_name)
DROP table table_name
5、插入记录，修改记录，删除记录
insert into zjt_tables select * from tables;
insert into zjt_views select * from views;
insert into test(id,phone) values(1,’5’);
update test set phone=’65356675’ where id=1;
delete from test where id=1;
6、建立视图
create view V_zjt_tables as select tabschema,tabname from zjt_tables;
7、建立触发器
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、删除唯一性索引
CREATE UNIQUE INDEX I_ztables_tabname
ON zjt_tables(tabname);
DROP index I_ztables_tabname
9、查看表
select tabname from tables
where tabname='ZJT_TABLES';
10、查看列
select SUBSTR(COLNAME,1,20) as 列名,TYPENAME as 类型,LENGTH as 长度
from columns
where tabname='ZJT_TABLES';
11、查看表结构
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、查看存贮过程
SELECT SUBSTR(PROCSCHEMA,1,15),SUBSTR(PROCNAME,1,15)
FROM SYSCAT.PROCEDURES;
16、类型转换(cast)
ip datatype:varchar
select cast(ip as integer)+50 from log_comm_failed
17、重新连接
connect reset
18、中断数据库连接
disconnect db2_gcb
19、view application
LIST APPLICATION;
20、kill application
FORCE APPLICATION(0);
db2 force applications all (强迫所有应用程序从数据库断开)
21、lock table
lock table test in exclusive mode
22、共享
lock table test in share mode
23、显示当前用户所有表
list tables
24、列出所有的系统表
list tables for system
25、显示当前活动数据库
list active databases
26、查看并设置命令选项
list command options
update command options using c off
27、系统数据库目录
LIST DATABASE DIRECTORY
28、表空间
list tablespaces
CREATE [{REGULAR | LARGE | SYSTEM TEMPORARY |
USER TEMPORARY}] TABLESPACE table_space_name
[PAGESIZE integer [K]]
MANAGED BY {SYSTEM | DATABASE}
USING (container_definition_string)
[BUFFERPOOL buffpool_name]
29、表空间容器
LIST TABLESPACE CONTAINERS FOR
Example: LIST TABLESPACE CONTAINERS FOR 1
30、显示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、表或视图特权
grant select,delete,insert,update on tables to user
grant all on tables to user WITH GRANT OPTION
34、程序包特权
GRANT EXECUTE
ON PACKAGE PACKAGE-name
TO PUBLIC
35、模式特权
GRANT CREATEIN ON SCHEMA SCHEMA-name TO USER
36、数据库特权
grant connect,createtab,dbadm on database to user
37、索引特权
grant control on index index-name to user
38、信息帮助 (? XXXnnnnn )
例:? SQL30081
39、SQL 帮助(说明 SQL 语句的语法)
help statement
例如，help SELECT
40、SQLSTATE 帮助(说明 SQL 的状态和类别代码)
? sqlstate 或 ? class-code
41、更改与"管理服务器"相关的口令
db2admin setid username password
42、创建 SAMPLE 数据库
db2sampl
db2sampl F:(指定安装盘)
43、使用操作系统命令
! dir
44、转换数据类型 (cast)
SELECT EMPNO, CAST(RESUME AS VARCHAR(370))
FROM EMP_RESUME
WHERE RESUME_FORMAT = 'ascii'
45、UDF
要运行 DB2 Java 存储过程或 UDF，还需要更新服务器上的 DB2 数据库管理程序配置，以包括在该机器上安装 JDK 的路径
db2 update dbm cfg using JDK11_PATH d:\sqllib\java\jdk
TERMINATE
update dbm cfg using SPM_NAME sample
46、检查 DB2 数据库管理程序配置
db2 get dbm cfg
47、检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
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、业务类型说明
insert into ywlbb values
('user01','业务申请'),
('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','改用户基本信息'),
('gl02','更改支付信息'),
('gl03','日统计功能'),
('gl04','冲帐功能'),
('gl05','对帐功能'),
('gl06','计费功能'),
('gl07','综合统计')
50、事务的提交、回滚
commit;
rollback;
51、查看db2的许可证信息
Db2licm –l
52、显示实例名称
Db2ilist
53、更新实例
Db2iupdt instance_name
54、DAS实例的配置信息
Db2 get admin cfg
55、其他实例的配置信息
Db2 get dbm cfg或者 db2 get database manager configuration
56、数据库的配置信息
Db2 get database configuration for database_name
57、创建工具目录数据库
db2 create tools catalog cc create new database toolsdb
58、数据库备份
CONNECT TO TAIS;
QUIESCE DATABASE IMMEDIATE FORCE CONNECTIONS;
CONNECT RESET;
BACKUP DATABASE TAIS TO "D:\backup" WITH 2 BUFFERS BUFFER 1024 PARALLELISM 1 WITHOUT PROMPTING;
CONNECT TO TAIS;
UNQUIESCE DATABASE;
59、数据库恢复
db2 restore database tais from d:\backup taken at 20061017 without rolling forward
60、切换实例（windows）
set db2instance=tais
61、创建全局临时表
a、创建用户临时表空间
db2 CREATE USER TEMPORARY TABLESPACE user_temp
MANAGED BY SYSTEM USING
('/home/inst##/usertemp')
b、创建全局临时表
DECLARE GLOBAL TEMPORARY TABLE table_name1
LIKE table_name2 NOT LOGGED
for example:
db2 DECLARE GLOBAL TEMPORARY TABLE temployee LIKE employee NOT LOGGED
c、查看创建过的临时表
select * from session.temployee
需要取消事务的自动落实(update command options using c off)
for example:
db2>CONNECT TO sample
db2>LIST COMMAND OPTIONS
db2>UPDATE COMMAND OPTIONS USING C OFF
db2>LIST COMMAND OPTIONS
db2>DECLARE GLOBAL TEMPORARY TABLE tstaff
LIKE staff NOT LOGGED
db2>INSERT INTO session.tstaff SELECT * FROM staff
db2>SELECT * FROM session.
staff
db2>COMMIT
db2>SELECT * FROM staff
db2>CONNECT RESET
62、创建模式名
CREATE SCHEMA schema_name AUTHORIZATION auth_name
63、断开当前的连接
db2 DISCONNECT CURRENT
64、创建视图
CREATE VIEW view_name (column_names)
AS fullselect
WITH {LOCAL|CASCADED} CHECK OPTION
for example:
CREATE view NEW.V3 AS SELECT * FROM NEW.SALES AS SALES;
CREATE view NEW.V4 AS SELECT * FROM NEW.SALES AS SALES WITH CASCADED CHECK OPTION;
CREATE view NEW.V5 AS SELECT * FROM NEW.SALES AS SALES WITH LOCAL CHECK OPTION;
65、创建序列
CREATE SEQUENCE ORG_SEQ
START WITH 1
INCREMENT BY 1
NO MAXVALUE
NO CYCLE
CACHE 24
--get sequence
values nextval for seq1
66、得到当前时间
values current timestamp
67、创建索引
type-2 indexes---对应用和并发进行保护,8版本以后使用
a、Unique index — Ensures uniqueness of key column(s) data
b、Bidirectional index（双向索引） — Allows scanning of indexes in either
direction
c、Clustered index（簇索引） — Places the rows of the table in the same
physical order as the index keys
d、多维索引---数据仓库中使用
CREATE UNIQUE INDEX index_name
ON table_name (column_name {ASC | DESC}
[, column_name {ASC | DESC}…])
INCLUDE column_names
CLUSTER
PCTFREE integer
MINPCTUSED integer
ALLOW REVERSE SCANS
CREATE INDEX in
ON employee(empno ASC)
PCTFREE 10
MINPCTUSED 40
Design Advisor in the CLP: db2advis
for example:
db2advis -d database_name
[{-w workload_name |
-s "sql_statement" |
-i filename}]
[-a userid[/password] ]
[-l disklimit]
[-t max_advise_time]
[-h]
[-p]
[-o out_file]
db2advis -d sample
-s "SELECT * FROM employee e WHERE firstnme
LIKE ’A%’"
-a inst00/inst00
-l 53
-t 20
exercises:
a、create normal index
CONNECT TO SAMPLE;
CREATE INDEX DB2ADMIN.IDX_STAFF_NAME ON NEW.STAFF ("NAME" ASC) PCTFREE 10 MINPCTUSED 10 COLLECT STATISTICS ;
COMMENT ON Index DB2ADMIN.IDX_STAFF_NAME IS 'common index on column name ';
CONNECT RESET;
b、create unique index
CONNECT TO SAMPLE;
CREATE UNIQUE INDEX DB2ADMIN.UIDX_STAFF_ID ON NEW.STAFF (ID ASC) PCTFREE 10 MINPCTUSED 10 COLLECT STATISTICS ;
CONNECT RESET;
c、create Bidirectional Index
CONNECT TO SAMPLE;
CREATE INDEX DB2ADMIN.BIDX_STAFF_SALARY ON NEW.STAFF (SALARY ASC) PCTFREE 10 MINPCTUSED 10 ALLOW REVERSE SCANS COLLECT DETAILED STATISTICS ;
CONNECT RESET;
d、Create Clustered Index
CONNECT TO SAMPLE;
CREATE INDEX DB2ADMIN.CIDX_STAFF_DEPT ON NEW.STAFF (DEPT ASC) CLUSTER PCTFREE 10 MINPCTUSED 10 COLLECT SAMPLED DETAILED STATISTICS ;
CONNECT RESET;
68、使用约束
Using Constraints(主键的字段不可为空，唯一键的字段可以为空)
a、Adding a Primary Key to an Existing Table
ALTER TABLE student ADD CONSTRAINT pk_id PRIMARY KEY(id)
exercises:
A、Use this command to create a new table called po_master
CREATE TABLE po_master (
po_no INTEGER NOT NU
LL,
po_date DATE NOT NULL,
bill_no INTEGER NOT NULL,
bill_date DATE NOT NULL,
description VARCHAR (200),
CONSTRAINT pk_po_master PRIMARY KEY (po_no),
CONSTRAINT u_key_bill_no UNIQUE (bill_no))
B、Use the following command to alter an existing table called po_master
ALTER TABLE po_master ADD CONSTRAINT u_key_bill_no UNIQUE (bill_no)
C、Using the CLP, create a table called po_master with a primary key on po_no using the following command
CREATE TABLE PO_DETAIL (
po_no INTEGER NOT NULL,
s_no INTEGER NOT NULL,
item_code INTEGER NOT NULL,
description VARCHAR (100),
quantity INTEGER NOT NULL,
rate INTEGER NOT NULL,
PRIMARY KEY (po_no, s_no),
CONSTRAINT fk_po_masterdetail FOREIGN KEY(po_no)
REFERENCES administrator.po_master (po_no))
D、There are four CREATE TABLE options for defining the delete rule:
NO ACTION,RESTRICT :If RESTRICT or NO ACTION is selected, an error occurs and no records are deleted if you try to delete records from parent table.
CASCADE: If CASCADE is selected, the delete operation is propagated to the dependent tables, that is, records in the po_master table as well as all the related records in the po_detail table are automatically deleted.
SET NULL: If SET NULL is selected, the delete operation in po_master table is allowed and the the related records in po_detail table are set to NULL.
E、modify table
---add restrict constraint(delete)
CONNECT TO SAMPLE;
ALTER TABLE DB2ADMIN.PO_DETAIL DROP FOREIGN KEY FK_PO_MASTERDETAIL ADD CONSTRAINT FK_PO_MASTERDETAIL FOREIGN KEY (PO_NO) REFERENCES DB2ADMIN.PO_MASTER (PO_NO) ON DELETE RESTRICT ON UPDATE NO ACTION ENFORCED ENABLE QUERY OPTIMIZATION ;
CONNECT RESET;
---add no action constraint(delete)
CONNECT TO SAMPLE;
ALTER TABLE DB2ADMIN.PO_DETAIL DROP FOREIGN KEY FK_PO_MASTERDETAIL ADD CONSTRAINT FK_PO_MASTERDETAIL FOREIGN KEY (PO_NO) REFERENCES DB2ADMIN.PO_MASTER (PO_NO) ON DELETE NO ACTION ON UPDATE NO ACTION ENFORCED ENABLE QUERY OPTIMIZATION ;
CONNECT RESET;
---add cascade constraint(delete)
CONNECT TO SAMPLE;
ALTER TABLE DB2ADMIN.PO_DETAIL DROP FOREIGN KEY FK_PO_MASTERDETAIL ADD CONSTRAINT FK_PO_MASTERDETAIL FOREIGN KEY (PO_NO) REFERENCES DB2ADMIN.PO_MASTER (PO_NO) ON DELETE CASCADE ON UPDATE NO ACTION ENFORCED ENABLE QUERY OPTIMIZATION ;
CONNECT RESET;
---add set null constraint(delete)
CONNECT TO SAMPLE;
ALTER TABLE DB2ADMIN.PO_DETAIL DROP FOREIGN KEY FK_PO_MASTERDETAIL ADD CONSTRAINT FK_PO_MASTERDETAIL FOREIGN KEY (PO_NO) REFERENCES DB2ADMIN.PO_MASTER (PO_NO) ON DELETE SET NULL ON UPDATE NO ACTION ENFORCED ENABLE QUERY OPTIMIZATION ;
CONNECT RESET;
---add restrict constraint(update)
CONNECT TO SAMPLE;
ALTER TABLE DB2ADMIN.PO_DETAIL DROP FOREIGN KEY FK_PO_MASTERDETAIL ADD CONSTRAINT FK_PO_MASTERDETAIL FOREIGN KEY (PO_NO) REFERENCES DB2ADMIN.PO_MASTER (PO_NO) ON DELETE RESTRICT ON UPDATE RESTRICT ENFORCED ENABLE QUERY OPTIMIZATION ;
CONNECT RESET;
---add no action constraint(update)
CONNECT TO
SAMPLE;
ALTER TABLE DB2ADMIN.PO_DETAIL DROP FOREIGN KEY FK_PO_MASTERDETAIL ADD CONSTRAINT FK_PO_MASTERDETAIL FOREIGN KEY (PO_NO) REFERENCES DB2ADMIN.PO_MASTER (PO_NO) ON DELETE RESTRICT ON UPDATE NO ACTION ENFORCED ENABLE QUERY OPTIMIZATION ;
CONNECT RESET;
F、Using Check Constraints
ALTER TABLE po_master ADD CONSTRAINT chk_bill_date CHECK (bill_date <= po_date)
69、导入导出数据
DB2 supports the following data formats for extraction and insertion:
◆ Delimited ASCII format (DEL)
◆ Integrated exchange format (IXF)
◆ Worksheet format (WSF)
◆ Non-delimited ASCII (ASC)
CONNECT TO SAMPLE;
EXPORT TO "C:\无界定字符" OF DEL MESSAGES "C:\无界定字符.log" SELECT * FROM NEW.EMPLOYEE;
CONNECT RESET;
CONNECT TO SAMPLE;
EXPORT TO "C:\界定字符" OF DEL MODIFIED BY COLDEL, MESSAGES "C:\界定字符.log" SELECT * FROM NEW.EMPLOYEE;
CONNECT RESET;
CONNECT TO SAMPLE;
EXPORT TO "C:\工作表格式" OF WSF MODIFIED BY 1 MESSAGES "C:\工作表格式.log" SELECT * FROM NEW.EMPLOYEE;
CONNECT RESET;
CONNECT TO SAMPLE;
EXPORT TO "C:\集成交换格式" OF IXF MESSAGES "C:\集成交换格式.log" SELECT * FROM NEW.EMPLOYEE;
CONNECT RESET;
CONNECT TO SAMPLE;
IMPORT FROM "C:\界定字符" OF DEL METHOD P (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14) MESSAGES "C:\界定字符.log" INSERT INTO DB2ADMIN.EMPLOYEE_DUP (EMPNO, FIRSTNME, MIDINIT, LASTNAME, WORKDEPT, PHONENO, HIREDATE, JOB, EDLEVEL, SEX, BIRTHDATE, SALARY, BONUS, COMM);
CONNECT RESET;
CONNECT TO SAMPLE;
IMPORT FROM "C:\工作表格式" OF WSF MESSAGES "C:\工作表格式.log" INSERT INTO DB2ADMIN.EMPLOYEE_DUP;
CONNECT RESET;
CONNECT TO SAMPLE;
IMPORT FROM "C:\集成交换格式" OF IXF MESSAGES "C:\集成交换格式.log" INSERT INTO DB2ADMIN.EMPLOYEE_DUP;
CONNECT RESET;
70、装载数据
db2 "CONNECT TO sample"
db2 "CREATE TABLE exc_emp LIKE employee"
db2 "ALTER TABLE exc_emp ADD COLUMN time TIMESTAMP"
db2 "ALTER TABLE exc_emp ADD COLUMN message CLOB(32K)"
db2 "CREATE TABLE employee_dup LIKE employee"
db2 "ALTER TABLE employee_dup ADD CONSTRAINT chk_cnst CHECK(EDLEVEL > 12)"
CONNECT TO SAMPLE;
LOAD FROM "C:\界定字符" OF DEL METHOD P (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14) MESSAGES "C:\界定字符.log" INSERT INTO DB2ADMIN.EMPLOYEE_DUP (EMPNO, FIRSTNME, MIDINIT, LASTNAME, WORKDEPT, PHONENO, HIREDATE, JOB, EDLEVEL, SEX, BIRTHDATE, SALARY, BONUS, COMM) COPY NO INDEXING MODE AUTOSELECT;
CONNECT RESET;
---check constraint
db2 SET INTEGRITY FOR employee_dup IMMEDIATE CHECKED FOR EXCEPTION IN employee_dup USE exc_emp
71、生成DDL语句
---single schema
db2look -d SAMPLE -z NEW -u DB2ADMIN -e -l -x -m -r ;
---full database
db2look -d SAMPLE -a -e -l -x -m -r -f ;
72、索和并发控制
DB2 provides different levels of protection to isolate data:
◆ Uncommitted read
◆ Cursor stability
◆ Read stability
◆ Repeatable read
---default isolation level
Cursor stability
exercise(using u
r isolation):
1.1 Open two Command Line Processor windows. We will refer to these windows
as W1 and W2. Make sure they connect to the correct instance before moving to the next
step.
1.2 Set the AUTOCOMMIT feature OFF in both W1 and W2 by executing this command:
db2 => update command options using c off
1.3 Change isolation level of W1 to uncommitted read.
db2 => CHANGE ISOLATION TO UR
db2 => CONNECT TO sample
1.4 Now go to W2 where the default isolation is cursor stability. Run these commands:
db2 => CONNECT TO sample
db2 => UPDATE staff SET salary = salary + 10
1.5 Go back to W1 and run the following statement to view dirty records from the staff table.
db2 => SELECT * FROM staff
You will see updated, but not committed data in W2. This is known as a dirty read.
1.6 Again switch to W2 and roll back the transaction.
db2 => ROLLBACK
1.7 Now, you can get actual data in W1:
db2 => SELECT * FROM staff
1.8 Close both windows W1 and W2.
exercise(Locking a Database)
The syntax for the CONNECT command is shown here:
CONNECT TO database_name [IN EXCLUSIVE MODE]
Execute the following command:
db2 CONNECT TO sample IN EXCLUSIVE MODE
USER your_login USING your_password
Now, try to connect to sample database as any user other than your_login. The following
message is returned:
db2 connect to sample user test using test
SQL1035N The database is currently in use. SQLSTATE=57019
73、出错处理
实例参数：diaglevel=3
日志文件：D:\IBM\SQLLIB\DB2
74、View Registry Variables
Use the db2set command to view registry variable values:
??db2set -i for instance-level parameters
??db2set -g for global-level parameters
??db2set -I for all the defined profiles
??db2set -all for all the registry variables with values
??db2set -lr for all available parameters
To set a parameter for the current instance:
??Syntax: db2set parameter=value
??Example: db2set DB2COMM=tcpip,npipe
To set a parameter’s value for a specific instance:
??Syntax: db2set parameter=value -i instance_name
??Example: db2set DB2COMM=tcpip,npipe -i altinst
To set a parameter at the global level:
??Syntax: db2set parameter=value -g
??Example: db2set DB2COMM=tcpip,npipe -g
75、Cataloging the Server
Syntax for cataloging a server:
CATALOG TCPIP NODE node_name
REMOTE {hostname | ip_address}
SERVER {svcename | port_number}
Example:
CATALOG TCPIP NODE db2serv REMOTE 9.186.128.141
SERVER 3700
76、cataloging the database
Syntax for cataloging a database:
CATALOG DATABASE db_name AS db_alias
AT NODE node_name
Example:
CATALOG DATABASE sample AS srv_samp
AT NODE db2server
二、目录视图说明
说明 目录视图
检查约束 SYSCAT.CHECKS
列 SYSCAT.COLUMNS
检查约束引用的列 SYSCAT.COLCHECKS
关键字中使用的列 SYSCAT.KEYCOLUSE
数据类型 SYSCAT.DATATYPES
函数参数或函数结果 SYSCAT.FUNCPARMS
参考约束 SYSCAT.REFERENCES
模式 SYSCAT.SCHEMATA
表约束 SYSCAT.TABCONST
表 SYSCAT.TABLES
触发器 SYSCAT.TRIGGERS
用户定义函数 SYSCAT.FUNCTIONS
视图 SYSCAT.VIEWS
三、字符串类型
二进制大对象 (BLOB) 字符串。
字符大对象 (CLOB) 字符串，它的字符序列可以是单字节字符或多字节字符，或这两者的组合。
双字节字符大对象 (DBCLOB) 字符串，它的字符序列是双字节字符。
四、数据库范式
第一种规范形式：表中的每一行和每一列均有一个值，永远不会是一组值。
第二种规范形式：不在关键字中的每一列提供取决于整个关键字的事实。
第三种规范形式：每个非关键字列提供与其他非关键字列无关并只取决于该关键字的事实。
第四种规范形式：没有行包含有关一个实体的两个或更多个独立的多值事实。
五、数据类型
数据类型 类型 特性 示例或范围
CHAR(15) 定长字符串 最大长度为 254 'Sunny day '
VARCHAR(15) 变长字符 最大长度为 4000 'Sunny day'
SMALLINT 数字 长度为 2 字节精度为 5 位 范围为-32768 至 32767
INTEGER 数字 长度为 4 字节精度为 10 位 范围为-2147483648 至 2147483647
REAL 数字 单精度浮点32 位近似值 范围为-3.402E+38至-1.175E-37或 1.175E-37 至-3.402E+38或零
DOUBLE 数字 双精度浮点64 位近似值 范围为-1.79769E+308 至-2.225E-307或 2.225E-307 至 1.79769E+308或零
DECIMAL(5,2) 数字 精度为 5小数位为 2 范围为 -10**31+1 至 10**31-1
DATE 日期时间 三部分值 1991-10-27
TIME 日期时间 三部分值 13.30.05
TIMESTAMP 日期时间 七部分值 1991-10-27-13.30.05.000000
六、列函数
列函数对列中的一组值进行运算以得到单个结果值。下列就是一些列函数的示例。
AVG
返回某一组中的值除以该组中值的个数的和
COUNT
返回一组行或值中行或值的个数
MAX
返回一组值中的最大值
MIN
返回一组值中的最小值
七、标量函数
标量函数对值进行某个运算以返回另一个值。下列就是一些由DB2 通用数据库提供的标量函数的示例。
ABS
返回数的绝对值
HEX
返回值的十六进制表示
LENGTH
返回自变量中的字节数（对于图形字符串则返回双字节字符数。）
YEAR
抽取日期时间值的年份部分
八、常见问题
1、初始化命令行环境
db2cmd
2、DB2 UDB体系结构
DB2 UDB 体系结构和数据库结构
图 1. DB2 UDB 体系结构
DB2 UDB 内存结构
? 包缓存 —— 为存储静态和动态 SQL 语句而分配的内存。
? 缓冲池 —— 在将数据刷新到磁盘之前，为存储数据而分配的内存。
? 日志缓冲区 —— 在将所有对数据库的更改刷新到磁盘上的日志之前，用来
存储这些更改的内存。
图 2. DB2 UDB 数据库结构
? 驱动器/目录 —— 在 CREATE DATABASE 命令中指定的驱动器或目录。
? DB2 实例名称 —— DB2 实例所有者的名称。
? NODE0000 —— 数据库的分区数。0 表示非分区的数据库。
? SQL00001 —— 从 1 开始的数据库 ID。
? SQLOGDIR —— 数据库的默认日志目录。
? SQLT0000.0 —— 目录表空间 SYSCATSPACE。
? SQLT0001.0 —— 临时表空间 TEMPSPACE1。
? SQLT0002.0 —— 用户表空间 USERSPACE1
3、WII的穿透技术
可以执行DML语句，并且可以使用其他数据库的函数
set passthru jiaozuo
set passthru reset