存储过程不从 db2 中删除记录

Question

CREATE OR REPLACE PROCEDURE  WRK.PURGE_ACH_BATCH_TAB_1()
LANGUAGE SQL

BEGIN
    -- Declare cursor
    DECLARE v_CNT_BLOCK INTEGER;
    DECLARE Ac_no BIGINT;
    DECLARE SQLSTATE CHAR(5) DEFAULT '00000'; 
    DECLARE mycur cursor for 
        SELECT t.TNX_Ac_no
        FROM WRK.BATCH_TAB1 c
            INNER JOIN WRK.BATCH_TAB t
                ON c.BATCH_ID = t.BATCH_ID
                    AND c.PROCESS_ID = t.process_ID
        WHERE c.BATCH_START_TS < (CURRENT DATE -7 days); 

    set v_CNT_BLOCK = 0;
    open mycur;

    FETCH FROM mycur INTO Ac_no;
    WHILE(SQLSTATE = '00000') DO
        DELETE FROM WRK.BATCH_TAB1 b WHERE b.TNX_Ac_no = Ac_no;
        SET v_CNT_BLOCK=v_CNT_BLOCK+1;
        if v_CNT_BLOCK >= 5 then
            set v_CNT_BLOCK = 0;
            commit;
        end if;

        FETCH FROM mycur INTO Ac_no;  

    END WHILE; 

    CLOSE mycur; 

    commit; 

END
@ 

我在 db2 表中有 19 条记录来满足分配给游标的条件，执行此命令后我得到了成功命令，但没有一个值从 db 中删除。请帮助我在哪里遗漏了什么。

Answer 1

看来您正试图从光标正在读取的同一个表中删除。根据您运行的隔离级别，您可能会遇到锁定错误。

在您的示例代码中，似乎没有任何理由首先使用光标。您应该删除该集合。

DELETE 
FROM WRK.BATCH_TAB1 c
WHERE EXISTS (SELECT 1 FROM WRK.BATCH_TAB t
               WHERE c.BATCH_ID = t.BATCH_ID
                 AND c.PROCESS_ID = t.process_ID
             )
AND c.BATCH_START_TS < (CURRENT DATE -7 days); 

鉴于对 cme​​ts 中相关性的修正：

DELETE 
FROM WRK.BATCH_TAB1 c
WHERE EXISTS (SELECT 1 FROM WRK.BATCH_TAB t
               WHERE c.BATCH_ID = t.BATCH_ID
                 AND c.PROCESS_ID = t.process_ID
                 AND t.BATCH_START_TS < (CURRENT DATE -7 days)
             );

或者，如果由于示例中不明显的原因必须使用光标，则应该查看 DELETE 语句的“定位形式”：

DELETE FROM WRK.BATCH_TAB1 WHERE CURRENT OF CURSOR mycur;

删除光标刚刚返回的记录。当然，使用INNER JOIN 时，它不适用于您原来的光标。但是，如果您使用我上面答案中的WHERE EXISTS 语法，则可以选择删除。

Answer 2

在足够新的 DB2 版本上，您应该能够执行以下操作：

BEGIN
 DECLARE SQLSTATE CHAR(5) DEFAULT '00000';
 loop1: WHILE SQLSTATE = '00000' DO
  DELETE FROM (
   SELECT FROM WRK.BATCH_TAB1 c
   WHERE EXISTS (SELECT 1 FROM WRK.BATCH_TAB t
               WHERE c.BATCH_ID = t.BATCH_ID
                 AND c.PROCESS_ID = t.process_ID
                 AND t.BATCH_START_TS < (CURRENT DATE -7 days)
   ) FETCH FIRST 5 ROWS ONLY
  );
  IF SQLSTATE = '02000' THEN -- not found
   LEAVE loop1;
  END IF;
  COMMIT;
 END WHILE;
END@