CREATE TABLE `student` (
`sid` char(10) NOT NULL,
`sname` varchar(20) CHARACTER SET latin1 DEFAULT NULL,
`gender` char(5) CHARACTER SET latin1 DEFAULT NULL,
`enter_age` int(11) DEFAULT NULL,
`enter_year` int(4) unsigned zerofill DEFAULT NULL,
`class` int(11) DEFAULT NULL,
PRIMARY KEY (`sid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
CREATE TABLE `course` (
`cid` char(7) NOT NULL,
`cname` char(20) CHARACTER SET latin1 DEFAULT NULL,
`tname` char(15) CHARACTER SET latin1 DEFAULT NULL,
`credithour` int(11) DEFAULT NULL,
`suigrade` year(4) DEFAULT NULL,
`cancleyear` int(4) unsigned zerofill DEFAULT NULL,
PRIMARY KEY (`cid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
CREATE TABLE `cinformation` (
`sid` char(10) NOT NULL,
`cid` char(7) NOT NULL,
`selyear` int(4) NOT NULL,
`` int(11) DEFAULT NULL,
PRIMARY KEY (`cid`,`sid`),
KEY `sid` (`sid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
第三个CINFORMATION的关系表建不了 老是提示ERRNO 150
`sid` char(10) NOT NULL,
`sname` varchar(20) CHARACTER SET latin1 DEFAULT NULL,
`gender` char(5) CHARACTER SET latin1 DEFAULT NULL,
`enter_age` int(11) DEFAULT NULL,
`enter_year` int(4) unsigned zerofill DEFAULT NULL,
`class` int(11) DEFAULT NULL,
PRIMARY KEY (`sid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
CREATE TABLE `course` (
`cid` char(7) NOT NULL,
`cname` char(20) CHARACTER SET latin1 DEFAULT NULL,
`tname` char(15) CHARACTER SET latin1 DEFAULT NULL,
`credithour` int(11) DEFAULT NULL,
`suigrade` year(4) DEFAULT NULL,
`cancleyear` int(4) unsigned zerofill DEFAULT NULL,
PRIMARY KEY (`cid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
CREATE TABLE `cinformation` (
`sid` char(10) NOT NULL,
`cid` char(7) NOT NULL,
`selyear` int(4) NOT NULL,
`` int(11) DEFAULT NULL,
PRIMARY KEY (`cid`,`sid`),
KEY `sid` (`sid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
第三个CINFORMATION的关系表建不了 老是提示ERRNO 150
第三张表根本在内部物理实现上与第一张和第二张没有关系。
没有外键约束。
不是字段同名就存在关系了。这不叫关系表啊。