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怎样有条件的分步删除数据表中的记录

敬业的IT人 互联网 佚名 2008-1-7 16:24:18

很多情况下我们需要分配删除数据表的一些记录,分批来提交以此来减少对于Undo的使用,下面我们提供一个简单的存储过程来实现此逻辑。

SQL> create table test as select * from dba_objects;Table created.SQL> create or replace procedure deleteTab 2 /** 3 ** Usage: run the script to create the proc deleteTab 4 ** in SQL*PLUS, type "exec deleteTab('Foo','ID>=1000000','3000');" 5 ** to delete the records in the table "Foo", commit per 3000 records. 6 ** Condition with default value '1=1' and default Commit batch is 10000. 7 **/ 8 ( 9 p_TableName in varchar2, -- The TableName which you want to delete from 10 p_Condition in varchar2 default '1=1', -- Delete condition, such as "id>=100000" 11 p_Count in varchar2 default '10000' -- Commit after delete How many records 12 ) 13 as 14 pragma autonomous_transaction; 15 n_delete number:=0; 16 begin 17 while 1=1 loop 18 EXECUTE IMMEDIATE 19 'delete from '||p_TableName||' where '||p_Condition||' and rownum <= :rn' 20 USING p_Count; 21 if SQL%NOTFOUND then 22 exit; 23 else 24 n_delete:=n_delete + SQL%ROWCOUNT; 25 end if; 26 commit; 27 end loop; 28 commit; 29 DBMS_OUTPUT.PUT_LINE('Finished!'); 30 DBMS_OUTPUT.PUT_LINE('Totally '||to_char(n_delete)||' records deleted!'); 31 end; 32 /Procedure created.SQL> insert into test select * from dba_objects;6374 rows created.SQL> /6374 rows created.SQL> /6374 rows created.SQL> commit;Commit complete.SQL> exec deleteTab('TEST','object_id >0','3000')Finished!Totally 19107 records deleted!PL/SQL procedure successfully completed.

注释:在此实例中修正了一下,增加了2个缺省值,以下是具体过程:

create or replace procedure deleteTab( p_TableName in varchar2, -- The TableName which you want to delete from p_Condition in varchar2 default '1=1', -- Delete condition, such as "id>=100000" p_Count in varchar2 default '10000' -- Commit after delete How many records ) as pragma autonomous_transaction; n_delete number:=0; begin while 1=1 loop EXECUTE IMMEDIATE 'delete from '||p_TableName||' where '||p_Condition||' and rownum <= :rn' USING p_Count; if SQL%NOTFOUND then exit; else n_delete:=n_delete + SQL%ROWCOUNT; end if; commit; end loop; commit; DBMS_OUTPUT.PUT_LINE('Finished!'); DBMS_OUTPUT.PUT_LINE('Totally '||to_char(n_delete)||' records deleted!');

注释:读者可以根据自己的实际情况来进行适当的调整。

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