mysql数据库异常处理代码实例

和C#中处理异常的方法很相像，mysql也有它自己处理异常的方法，本文列出了mysql处理实例的代码，通过代码我们来了解mysql数据库处理异常的原理和方法。
具体的实例代码如下：

DROP PROCEDURE IF EXISTS sp_call_jobs;  
 
CREATE PROCEDURE sp_call_jobs（）  
 
NOT DETERMINISTIC  
 
SQL SECURITY DEFINER  
 
COMMENT ''  
 
BEGIN  
 
declare _row,_err,_count int default 0;  
 
DECLARE CONTINUE HANDLER FOR SQLEXCEPTION,SQLWARNING,NOT FOUND set _err=1;  
 
while _row<3 DO  
 
START TRANSACTION;  
 
insert into t1（cond_val）values（null）；  
 
COMMIT;  
 
if _err=1 then  
 
set _count_count=_count+1;  
 
end if;  
 
set _row_row=_row+1;  
 
end while;  
 
select _count;  
 
END; 

语句：

DECLARE CONTINUE HANDLER FOR SQLEXCEPTION,SQLWARNING,NOT FOUND set _err=1;

作用是当遇到SQLEXCEPTION,SQLWARNING,NOT FOUND 错误时，设置_err=1并执行CONTINUE操作，即继续执行后面的语句。

而且在执行可能出错的语句的时候我们用事务语句：START TRANSACTION; …… COMMIT; 可以保证完整性。

DELIMITER $$

DROP PROCEDURE IF EXISTS `vm`.`sp_DelItem`$$


CREATE DEFINER=`root`@`localhost` PROCEDURE `sp_DelItem`(IN nType int,IN nLsh int,IN nChanNo int,OUT nRetNum int)
BEGIN
declare _err int default 0;  
declare nChanNum int;
DECLARE CONTINUE HANDLER FOR SQLEXCEPTION,SQLWARNING,NOT FOUND set _err=1;
set nRetNum = 0;
START TRANSACTION; 
set nChanNum = 0;
if nType = 0 then
delete from USERRIGHT where USERLSH in (select LSH from USR where REGIONALISMLSH=nLsh);
delete from USR where REGIONALISMLSH = nLsh;
delete from REGIONALISM where LSH = nLsh;
end if; 
 
 
if (nType = 1) then
delete from MEDIASRV where LSH = nLsh;
end if;
if (nType = 2) then
delete from CHANNEL where NETDVRLSH = nLsh;
delete from USERRIGHT where NETDVRLSH = nLsh;
delete from NETDVR where LSH =nLsh;
end if;
if (nType = 3) then
delete from USERRIGHT where CHANNO = nChanNo and NETDVRLSH = nLsh;
update NETDVR set CHANNUM = CHANNUM - 1 where LSH = nLsh;
delete from CHANNEL where CHANNO = nChanNo and NETDVRLSH = nLsh;
end if;
if (nType = 4) then
delete from USERRIGHT where USERLSH = nLsh;
delete from USR where LSH = nLsh;
end if;
 
COMMIT;  
 
 if _err=1 then  
 
set nRetNum = 1;
Rollback;
 
end if; 
   
 
select nRetNum; 
    END$$


DELIMITER ;