修改表级联与级联操作

example：

Alter table demo.cmi_wx_info
add foreign key (CUST_ID) references demo.cmi_customer_info(CUST_ID) on update Cascade on delete Cascade

这样修改表当

CREATE TABLE user (
id int(4) NOT NULL,
sex enum(‘f’,’m’) DEFAULT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

CREATE TABLE userinfo (
sn int(4) NOT NULL AUTO_INCREMENT,
userid int(4) NOT NULL,
info varchar(20) DEFAULT NULL,
PRIMARY KEY (sn),
KEY userid (userid),
CONSTRAINT userinfo_ibfk_1 FOREIGN KEY (userid) REFERENCES user (id) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

http://blog.csdn.net/wslyy99/article/details/4336602

http://blog.csdn.net/langcai1981/article/details/25322087

http://blog.csdn.net/sunzhenhua0608/article/details/8948120