怎样有条件的分步删除数据表中的记录

来源：赛迪网    作者：fennazha

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。