转载地址：http://blog.csdn.net/donglynn/article/details/17056099
错误
SQL 查询:
DELETE FROM `zmax_lang` WHERE CONVERT( `zmax_lang`.`lang` USING utf8 ) = 'fr' LIMIT 1
MySQL 返回：
#1451 - Cannot delete or update a parent row: a foreign key constraint fails (`myreview/zmax_text`, CONSTRAINT `zmax_text_ibfk_1` FOREIGN KEY (`lang`) REFERENCES `zmax_lang` (`lang`))
以上是因为，改条记录的某个字段作为innodb的另外一个表的外链。而在删除操作时会自动检查外链。解决的办法之一是，不检查外链，只需将执行语句前加上下句即可：
SET FOREIGN_KEY_CHECKS = 0;
DELETE FROM `zmax_lang` WHERE CONVERT( `zmax_lang`.`lang` USING utf8 ) = 'fr' LIMIT 1
