MySQL无法添加外键,error code: 1215. cannot add foreign key constraint
比如创建两个简单的表,如下。CREATEtableclazz(idINTAUTO_INCREMENT,~~~~namevarchar(20)NOTNULL,totalINTUNSIGNEDNOTNULL,PRIMARYKEY(id))ENGINE=InnoDBDEFAULTCHARSET=utf8;CREATEtablestudent(idINTAUTO_INCREMENT,namevarchar