SYBASE 数据库迁移到AS 400 db2的FAQ(一)

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笔者通过从事数据库的开发和管理工作数年!前不久刚刚完成SYBASE 数据库向db2数据库的迁移项目工作!

应网友和一些同学朋友的要求!要我介绍一些数据库迁移的策略和方法!

目前见于网上数据库迁移的资料较少!我实际工作中的遇到的技术难点和解决的策略和方法,简单介绍!希望对想要迁移数据库,又不知道如何下手的朋友有所借鉴!本文列出51个实际中问题和解决的策略和方法!非常注重实际!

ASs=MsoNormal>1AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.SYBASEAScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">数据类型和db2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">有那些不同?

ASs=MsoNormal>答:Datetime  对应 timestampAS-microsoft-com:office:office" />

ASs=MsoNormal>Tinyint ,smallint  对应  smallint

ASs=MsoNormal>Money 类型对应 numeric(19,4)

ASs=MsoNormal> 

ASs=MsoNormal>2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.db2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">数据库是否支持自增加列设置?

ASs=MsoNormal>答:支持,例如:SYSID  BIGINT GENERATED ALWAYS AS IDENTITY

ASs=MsoNormal>将原来sysid 的  numerical(18,0) 改为 BIGINT类型

ASs=MsoNormal> 

ASs=MsoNormal>3AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.db2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">是否有convert()AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数,SYBASE AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">下这样语句如何转换?

ASs=MsoNormal>答:convert(datetime,convert(char(8),dateadd(day,-1,getdate()),112))

ASs=MsoNormal>db2下没有convert()函数,关于转换可以使用如下函数

ASs=MsoNormal>char(),timestamp(),date(),time() …另外可以使用系统内部的系统变量

ASs=MsoNormal>current timestamp , current date , current time 代表系统当前日期时间

ASs=MsoNormal>如上语句可以这样转换

ASs=MsoNormal>timestamp( current date –1 days,time(’00.00.00’))

ASs=MsoNormal>4AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.SYBASEAScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的isnull(@vc_pici_id,’0’) AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">如何转换?

ASt-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: 'Times New Roman'">答:db2下使用value(vc_pici_id,’0’)或者coalesce(vc_pici_id,’0’)

ASt-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: 'Times New Roman'">

ASt-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareASt-font-family: 宋体"> 

ASs=MsoNormal>5AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.db2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">下如何调用存储过程和调用代返回值得存储过程?

ASs=MsoNormal>答: (1)无返回参数调用CALL proc1(v_empno, v_salary)

ASs=MsoNormal>(2)有返回参数调用

ASs=MsoNormal>declare ret_var integer  default 0;

ASs=MsoNormal>CALL proc1(var1,var2) ;

ASs=MsoNormal>Get Diagnostics ret_var = RETURN_STATUS;

ASs=MsoNormal>---------

ASs=MsoNormal>declare err_code integer default 0;

ASs=MsoNormal>call   proc1(var1,err_code);

ASs=MsoNormal>IF ERR_CODE  = 1 THEN

ASs=MsoNormal>XXXX;

ASs=MsoNormal>END IF;

ASs=MsoNormal>6AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.SYBASE AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">下游标控制是非常方便的,使用sqlcode,sqlstateAScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">来控制,不知道db2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">下游标是如何控制的?

ASs=MsoNormal>答:db2下游标控制不是非常的轻松和方便的,同样也可以使用sqlcode,sqlstate,或者用户自己控制,db2下SQLCODE,SQLSTATE不能直接使用,必须声明后使用,(也就是说将系统的SQLCODE,SQLSTATE本地实例化一分拷贝)。一般采用用户定义游标开关和sqlcode返回信息一起共同控制的方法.

ASs=MsoNormal>举例1:(这里说明一个问题,游标开关是和SQLCODE捆绑的。‘02000’就是SQLCODE号)

ASs=MsoNormal>//-------

ASs=MsoNormal>标准使用游标的例子

ASs=MsoNormal>标准WHILE DO 控制游标

ASs=MsoNormal>//-------

ASs=MsoNormal> 

ASs=MsoNormal> 

ASs=MsoNormal>CREATE PROCEDURE CREDITP             

ASs=MsoNormal>(IN i_perinc DECIMAL(3,2),

ASs=MsoNormal>INOUT o_numrec DECIMAL(5,0))

ASs=MsoNormal>LANGUAGE SQL

ASs=MsoNormal>BEGIN                                      -- 这里是用户管理事务

ASs=MsoNormal>DECLARE proc_cusnbr CHAR(5);

ASs=MsoNormal>DECLARE proc_cuscrd DECIMAL(11,2);

ASs=MsoNormal>DECLARE numrec DECIMAL(5,0);

ASs=MsoNormal>DECLARE at_end INT DEFAULT 0;              -- 开关定义                     

ASs=MsoNormal>DECLARE not_found  CONDITION FOR '02000';  -- 没有数据,游标结尾定义                              

ASs=MsoNormal>DECLARE c1 CURSOR FOR SELECT cusnbr, cuscrd  FROM ordapplib.customer;

ASs=MsoNormal> 

ASs=MsoNormal>DECLARE CONTINUE HANDLER FOR not_found SET at_end = 1;        --定义CONTINUE 条件

ASs=MsoNormal> 

ASs=MsoNormal>DECLARE EXIT HANDLER FOR SQLEXCEPTION     ROLLBACK ;          --sqlcode 非'01''00''02'则退出并回滚事务

ASs=MsoNormal>SET numrec = 0;

ASs=MsoNormal> 

ASs=MsoNormal>OPEN c1;

ASs=MsoNormal>    FETCH c1 INTO proc_cusnbr, proc_cuscrd;

ASs=MsoNormal>WHILE at_end = 0 DO

ASs=MsoNormal>    SET proc_cuscrd = proc_cuscrd +(proc_cuscrd * i_perinc);

ASs=MsoNormal>    SET numrec = numrec + 1;

ASs=MsoNormal>    FETCH c1 INTO proc_cusnbr, proc_cuscrd;

ASs=MsoNormal>END WHILE;

ASs=MsoNormal>SET o_numrec = numrec;

ASs=MsoNormal>CLOSE c1;

ASs=MsoNormal>COMMIT;           --提交事务                

ASs=MsoNormal>END

ASs=MsoNormal> 

ASs=MsoNormal>举例2:

ASs=MsoNormal>--声明游标C1

ASs=MsoNormal>DECLARE c1 CURSOR FOR

ASs=MsoNormal>SELECT cusnbr, cuscrd

ASs=MsoNormal>FROM ordapplib.customer;

ASs=MsoNormal> 

ASs=MsoNormal>OPEN c1; --打开游标

ASs=MsoNormal>FETCH c1 INTO proc_cusnbr, proc_cuscrd; --从游标获取数据

ASs=MsoNormal>IF SQLSTATE = '02000' THEN  --判断游标是否有数据(无)

ASs=MsoNormal>CALL DATA_NOT_FOUND;    --返回调用

ASs=MsoNormal>ELSE

ASs=MsoNormal>DO WHILE (SUBSTR(SQLSTATE,1,2) = '00' | SUBSTR(SQLSTATE,1,2) = '01');

ASs=MsoNormal>FETCH c1 INTO proc_cusnbr, proc_cuscrd;

ASs=MsoNormal>......

ASs=MsoNormal> 

ASs=MsoNormal>END IF ;

ASs=MsoNormal>CLOSE c1;  --关闭游标

ASs=MsoNormal> 

ASs=MsoNormal>7AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.db2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">存储过程的标准格式如何?

ASs=MsoNormal>答:db2存储过程的编写比较灵活,但是语法格式是非常严格的。基本如下

ASs=MsoNormal>   CTEATE  PROCEDURE  XHZQ_db.PROCNAME (

ASs=MsoNormal>IN  PARA_1  TYPE  DEFAULT  VALUE ,

ASs=MsoNormal>OUT PARA_2 TYPE  DEFAULT  VALUE)

ASs=MsoNormal>BEGIN   ( 用户管理事务)

ASs=MsoNormal>--用户定义变量

ASs=MsoNormal>DECLARE   VAR1  TYPE  DEFAULT  VALUE;

ASs=MsoNormal>--用户定义控制临时变量

ASs=MsoNormal>DECLARE   ERROR_CODE INT DEFAULT 0;

ASs=MsoNormal>DECLARE   AT_END  INT  DEFAULT 0;

ASs=MsoNormal>-- 用户定义条件控制变量

ASs=MsoNormal>DECLARE not_found  CONDITION FOR '02000';

ASs=MsoNormal>-- 用户定义游标

ASs=MsoNormal>DECLARE  C1  CURSOR  FOR  SELECT  COL  FROM   TABLE_NAME ;

ASs=MsoNormal> 

ASs=MsoNormal>-- 用户定义条件和开关变量关联

ASs=MsoNormal>DECLARE CONTINUE HANDLER FOR not_found SET at_end = 1;

ASs=MsoNormal>-- 用户定义事务回滚处理条件

ASs=MsoNormal>DECLARE EXIT HANDLER FOR SQLEXCEPTION     ROLLBACK ;

ASs=MsoNormal>-- 初始化变量直

ASs=MsoNormal>SET  VAR  = 0;

ASs=MsoNormal>-- 判断入口参数

ASs=MsoNormal>IF (PARA_1 IS NULL) THEN

ASs=MsoNormal>SET  PARA =  100;

ASs=MsoNormal>END IF;

ASs=MsoNormal> 

ASs=MsoNormal>-- 存储过程语句体集合

ASs=MsoNormal>OPEN  C1 ;

ASs=MsoNormal>FETCH  C1 INTO  XX,XX2,XX3  ;

ASs=MsoNormal>….

ASs=MsoNormal>CLOSE  C1;

ASs=MsoNormal>-- 提交事务

ASs=MsoNormal>COMMIT WORK HOLD;

ASs=MsoNormal>SET PARA_2 = 0 ;

ASs=MsoNormal>RETURN  PARA_2 ; 

ASs=MsoNormal>-- 返回参数0 成功

ASs=MsoNormal>ASt-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: 'Times New Roman'">END

ASs=MsoNormal>ASt-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: 'Times New Roman'"> 

ASs=MsoNormal>8AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.db2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">下char()AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数用法

ASs=MsoNormal>答: CHAR(DATE,Keyword)  , CHAR(TIME,Keyword)

ASs=MsoNormal>

ASs=MsoNormal>Keyword

ASs=MsoNormal>Date Format

ASs=MsoNormal>Time Format

ASs=MsoNormal>USA

ASs=MsoNormal>07/17/2001

ASs=MsoNormal>01:48PM

ASs=MsoNormal>ISO

ASs=MsoNormal>2001-07-17

ASs=MsoNormal>13.48.04

ASs=MsoNormal>EUR

ASs=MsoNormal>17.07.2001

ASs=MsoNormal>13.48.04

ASs=MsoNormal>JIS

ASs=MsoNormal>2001-07-17

ASs=MsoNormal>13.48.04

ASs=MsoNormal>Select CURRENT DATE,CURRENT TIME From SYSIBM>SYSDUMMY1;

ASs=MsoNormal> 

ASs=MsoNormal> 

ASs=MsoNormal>9AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.db2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">下timestamp()AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数用法

ASs=MsoNormal>答:TIMESTAMPDIFF(K,CHAR(TS1 – TS2))

ASs=MsoNormal>

ASs=MsoNormal>K

ASs=MsoNormal>Date Part

ASs=MsoNormal>K

ASs=MsoNormal>Date Part

ASs=MsoNormal>256

ASs=MsoNormal>Years

ASs=MsoNormal>128

ASs=MsoNormal>Quarters

ASs=MsoNormal>64

ASs=MsoNormal>Months

ASs=MsoNormal>32

ASs=MsoNormal>Weeks

ASs=MsoNormal>16

ASs=MsoNormal>Days

ASs=MsoNormal>8

ASs=MsoNormal>Hours

ASs=MsoNormal>4

ASs=MsoNormal>Minutes

ASs=MsoNormal>2

ASs=MsoNormal>Seconds

ASs=MsoNormal> 

ASs=MsoNormal>10AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">.db2AScii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">下如何进行字符串组合拼接?

ASs=MsoNormal>答:使用‘||’处理,concat()函数

ASs=MsoNormal>  例如: DECLARE   VC_SQL_STR   VCHAR(100);

ASs=MsoNormal>         DECLARE   VC_WHERE    VCHAR(100);

ASs=MsoNormal>         DECLARE   VC_FROM     VCHAR(100);

ASs=MsoNormal>         SET VC_FROM = ‘ FROM XHZQ_db.SYS_PARAMETER_TAB ‘;

ASs=MsoNormal>         SET VC_WHERE = ‘ WHERE VC_ID IS NULL ‘;

ASs=MsoNormal>        SET  VC_SQL_STR = ‘ SELECT * ‘ || VC_FROM || VC_WHERE  ;

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