net start mysql 连接数据库
mysql -u 用户名 -p 密码登陆
create database 库名; //创建数据库
create table `student`(
id int(20) primary key not null,
name varchar(255),
tid int(20)); //创表
create table `teacher`(
tid int(20),
tname varchar(255));
alter table teacher add constaraint teacher_pk primary key teacher(tid); //添加主键
alter table student add constaraint student_fk_teacher foreign key(tid) references teacher(tid); //添加外键
alter table student rename stu; //更换表名
alter table stu add age int(20); //添加字段
alter table stu change age aihao varchar(20); //修改字段
alter table stu drop aihao; //删除字段