一起执行 会报错 !!把最后一句(红字的)删掉 就没问题了!我看网上的外键是这么写的,请来帮忙看看怎么改!或有别的写法吗?
use test;
create table user(`id` int not null AUTO_INCREMENT, `username` varchar(20) not null,`password` varchar(10) not null,`birthday` date not null,primary key(`id`));create table music(`id` int not null auto_increment,`songnm` varchar(50) not null,`singer` varchar(50) not null ,`classid` varchar(20) not null ,`licyer` blob ,`special` varchar(15) ,`song`varchar(25) not null,`specialpic` varchar(25),primary key(`id`));create table class(`id` int not null auto_increment,`classname` varchar(15) not null ,primary key(`id`) );alter table music ADD INDEX idx_classid(`classid`);
alter table class ADD INDEX idx_id(`id`);
alter table music ADD CONSTRAINT fk_classid FOREIGN KEY(`classid`) REFERENCES class(`id`);
use test;
create table user(`id` int not null AUTO_INCREMENT, `username` varchar(20) not null,`password` varchar(10) not null,`birthday` date not null,primary key(`id`));create table music(`id` int not null auto_increment,`songnm` varchar(50) not null,`singer` varchar(50) not null ,`classid` varchar(20) not null ,`licyer` blob ,`special` varchar(15) ,`song`varchar(25) not null,`specialpic` varchar(25),primary key(`id`));create table class(`id` int not null auto_increment,`classname` varchar(15) not null ,primary key(`id`) );alter table music ADD INDEX idx_classid(`classid`);
alter table class ADD INDEX idx_id(`id`);
alter table music ADD CONSTRAINT fk_classid FOREIGN KEY(`classid`) REFERENCES class(`id`);
create table `user`
(`id` int not null AUTO_INCREMENT,
`username` varchar(20) not null,
`password` varchar(10) not null,
`birthday` date not null,
primary key(`id`)
) engine innodb;create table music
(`id` int not null auto_increment,
`songnm` varchar(50) not null,
`singer` varchar(50) not null ,
`classid` int not null ,
`licyer` blob ,
`special` varchar(15) ,
`song`varchar(25) not null,
`specialpic` varchar(25),
primary key(`id`)
) engine innodb;create table class
(`id` int not null auto_increment,
`classname` varchar(15) not null,
primary key(`id`)
) engine innodb;alter table music ADD INDEX idx_classid(`classid`);
alter table music ADD CONSTRAINT fk_classid FOREIGN KEY (`classid`) REFERENCES class(`id`);
改后的:
use test;create table user(`id` int not null AUTO_INCREMENT, `username` varchar(20) not null,`password` varchar(10) not null,`birthday` date not null,primary key(`id`));
create table music(`id` int not null auto_increment,`songnm` varchar(50) not null,`singer` varchar(50) not null ,`classid` int not null ,`licyer` blob ,`special` varchar(15) ,`song`varchar(25) not null,`specialpic` varchar(25),primary key(`id`));create table class(`id` int not null auto_increment,`classname` varchar(15) not null ,primary key(`id`) );
alter table music ADD INDEX idx_classid(`classid`);alter table music ADD CONSTRAINT fk_classid FOREIGN KEY(`classid`) REFERENCES class(`id`);