mysql经典语句(外键开关)

-- 查找所有表的语句

select table_name 

from information_schema.tables 
where table_schema='当前数据库名'

--外键

drop table if EXISTS `userinfo`;

create table `userinfo`(
`id` int(10) primary key auto_increment,
`username` varchar(50) not null,
`userpwd` varchar(50) not null,
`pic` varchar(64) not null

)engine=innodb default CHARSET=utf8;

drop table if exists `attendance1`;

create table `attendance1`(
`id` int(10) primary key auto_increment,
`creatime1` datetime not null,
`state` int(5) default 1 not null,
`name1` varchar(20) not null ,
`remark` varchar(50),
`userid` int(8) not null,
key `fk_attendance1_userid`(`userid`),
constraint `fk_attendance1_userid` foreign key(`userid`) references `userinfo`(`id`)

)engine=innodb default CHARSET=utf8;

--外键开关

-- 外键关 
SET FOREIGN_KEY_CHECKS=0;

-- 外键开 
SET FOREIGN_KEY_CHECKS=1;