我正在使用这里所示的存储过程,通过参数化表名、提交次数和where条件来删除12个巨大的表。我已经将这3条信息插入到一个叫做 PURGE_DEL
其中有12行,我想知道如何从12个表中逐一读取,自动删除。
比如说
表名:PURGE_DEL
CALL DELETE_DATA(PURGE_DEL.TABLE_NAME, PURGE_DEL.COMMIT_COUNT, PURGE_DEL.WHERE)
代码。
CREATE PROCEDURE DELETE_DATA
(IN V_TABLE_NAME VARCHAR(24),
IN V_COMMIT_COUNT INTEGER,
IN V_WHERE_CONDITION VARCHAR(1024))
DYNAMIC RESULT SETS 01
COMMIT ON RETURN NO
LANGUAGE SQL
NOT DETERMINISTIC
L3 : BEGIN
-- DECLARE STATEMENTS
DECLARE SQLCODE INTEGER;
DECLARE V_DELETE_QUERY VARCHAR(1024);
DECLARE V_DELETE_STATEMENT STATEMENT;
SET V_DELETE_QUERY = 'DELETE FROM ' || V_TABLE_NAME ||
' WHERE COLUMN IN (SELECT COLUMN FROM '
|| V_TABLE_NAME || 'WHERE COLUMN_ID ='
|| V_WHERE_CONDITION || ' FETCH FIRST '
|| RTRIM(CHAR(V_COMMIT_COUNT)) || ' ROWS ONLY) ';
PREPARE V_DELETE_STATEMENT FROM V_DELETE_QUERY;
DEL_LOOP:
LOOP
EXECUTE V_DELETE_STATEMENT;
IF SQLCODE = 100 THEN
LEAVE DEL_LOOP;
END IF;
COMMIT;
END LOOP;
COMMIT;
END L3
也请对存储过程提出任何修改建议。
出于兴趣,你可以在DELETE中使用这种风格的DELETE来避免代价高昂的自连接。
DELETE FROM (
SELECT 1 FROM TABLE_NAME
WHERE WHERE_CONDITION
FETCH FIRST 50000 ROWS ONLY
)
而且,如果您真的想要高效地清除行,您可以考虑使用MDC滚动删除。
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