Foreign key names in the same database when you create a foreign key table cannot use the same

CREATE TABLE day_news (id smallint unsigned auto_increment, title varchar (), content text, author varchar (20    0), Num int unsigned default 0, ntime int unsigned, CNAME varchar (x), hotarticle enum (' Y ', ' n ') default ' n ', Flag enum (' Y ', ' n ') default ' Y ', primary key (ID), Constraint NFK foreign key (CNAME) references Day_newsclass (CNAME ) on delete set NULL on UPDATE cascade) ENGINE=INNODB default Charset=utf8;select * from Day_newsclass;select * from Day_ne Ws;truncate day_news;truncate day_newsclass;delete from Day_newsclass where 1=1;select * from Day_newsclass;



In addition, the foreign key is NFK must change the name

From for notes (Wiz)

Foreign key names in the same database when you create a foreign key table cannot use the same