Mysql錯誤問題:ERROR 1005 (HY000): Can't create table 'crm_1.tbl_client' (errno: 150)

MySQL外鍵創建條件:

1.兩個表必須是InnoDB數據引擎
2.外鍵表的外鍵字段必須是主鍵
3.字段類型必須一致

創建表時創建外鍵:

 create table tbl_client(userName varchar(255) not null, address varchar(255), createDate timestamp not null default now(), createUserName varchar(255), foreign key(createUserName) references tbl_user(userName));