Question

MySQL联级操作，下面的代码不知道哪里错了,MySQL5.7版本

CREATE TABLE a (
name char(20) NOT NULL,
id char(20) NOT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

create table b(
　　b_name char(20) not null,
　　b_id char(20) not null,
　　constraint kf_1 foreign key(b_id)
references a(id) on delete cascade on updata cascade)ENGINE=InnoDB DEFAULT CHARSET=utf8;
----------------------------------------------------------------------------------------------------------------------------------
创建b表的时候出现下面的错误，错在哪了呢？

1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'kf_1 foreign key(b_id)
references a(id) on delete cascade on updata cascad' at line 4

Answer 1

外键可以是自己表中的字段么。。