sql - 相同数据更新的例外

Question

在异常处理方面需要帮助。如果我运行这个 UPDATE 脚本一旦它工作，但是当我运行相同的脚本两次或多次时，我会收到以下错误“1 row updated.commited”，但它不正常。我想收到异常。“注意：表格已经更新”

UPDATE FBTB_TXNLOG
SET txnstageid = '-1',
LOCKED = 'N',
where xrefid = 'FJB1229000056689';
commit;

Answer 1

试试这个解决方案：

SET SERVEROUTPUT ON -- need for dbms_output.put_line()
declare 
  cnt int;
begin
  -- if data exists 
  SELECT count(1)  
  INTO   cnt
  FROM   FBTB_TXNLOG
  WHERE   txnstageid = '-1'
  and  LOCKED = 'N'
  and xrefid = 'FJB1229000056689';

 if (cnt > 0 ) 
 then  
   -- exists: display message
   dbms_output.put_line('Table is already updated');  
 else
   -- let's edit 
   UPDATE FBTB_TXNLOG
   SET txnstageid = '-1',
       LOCKED = 'N',
   where xrefid = 'FJB1229000056689';
   commit;
 end if; 
end;
/