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我有 2 个表,第一个是 smsusers(id,fname,lname,userid)
'id' 是主键,
userid
是唯一键
address_detail(id,address,type);
这里我想将 smsusers
的 userid
作为外键添加到 address_detail
表。
为此,我在 address_detail
中添加了一列作为 user_id
ALTER TABLE address_detail add user_id INT( 20 ) default NULL;
现在我正在为表添加外键约束
ALTER TABLE `address_detail` add CONSTRAINT address_detail_fk FOREIGN KEY (user_id)
REFERENCES smsusers ('userid') ON UPDATE CASCADE ON DELETE CASCADE;
这一步出现以下错误
#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 ''userid') ON
UPDATE CASCADE ON DELETE CASCADE' at line 1