创建db5数据库
create database db5 charset=utf8;
use db5;
例二：一个管理员唯一对应一个用户
用户表：
id user password
1 egon xxxx
2 alex yyyy
创建用户表mysql> create table user(
id int primary key auto_increment,
user varchar(50) not null,
password varchar(50) not null);
Query OK, 0 rows affected (0.12 sec)
插入用户信息
mysql> insert into user(user,password) values('alex',''),('mike',''),('jack','');
Query OK, 3 rows affected (0.01 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> select * from user;
+----+------+----------+
| id | user | password |
+----+------+----------+
| 1 | alex | 123 |
| 2 | mike | 1234 |
| 3 | jack | 123 |
+----+------+----------+
3 rows in set (0.00 sec)
管理员表：
fk+unique
id user_id password
1 1 xxxxx
2 2 yyyyy
创建管理员表mysql> create table Administrator(
id int primary key auto_increment,
user_id int unique,
password varchar(50) not null,
foreign key(user_id) references user(id)
on delete cascade
on update cascade);
Query OK, 0 rows affected (0.20 sec)
插入记录
mysql> insert into Administrator(user_id,password) values(1,''),(2,''),(3,'');
Query OK, 3 rows affected (0.01 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> select * from Administrator;
+----+---------+----------+
| id | user_id | password |
+----+---------+----------+
| 1 | 1 | 123 |
| 2 | 2 | 1234 |
| 3 | 3 | 123 |
+----+---------+----------+
3 rows in set (0.00 sec)