目录

1、创建数据库Market，在 Market中创建数据表customers。​编辑

2、在Market中创建数据表orders。

3、创建数据库Team，定义数据表player。

1、创建数据库Market，在 Market中创建数据表customers。

（1）mysql> create database Market;
Query OK, 1 row affected (0.00 sec)

mysql> use Market;
Database changed
（2）mysql> create table customers(
    -> c_num int(11) primary key auto_increment,
    -> c_name varchar(50),
    -> c_contact varchar(50),
    -> c_city varchar(50),
    -> c_birth datetime not null);
Query OK, 0 rows affected (0.02 sec)

（3）mysql> alter table customers modify c_birth datetime  after c_contact;

Query OK, 0 rows affected (0.02 sec)
Records: 0  Duplicates: 0  Warnings: 0

（4）mysql> alter table customers modify c_name varchar(70);
Query OK, 0 rows affected (0.00 sec)
Records: 0  Duplicates: 0  Warnings: 0

（5）mysql> alter table customers change c_contact c_phone varchar(50);
Query OK, 0 rows affected (0.00 sec)
Records: 0  Duplicates: 0  Warnings: 0

（6）mysql> alter table customers add c_gender char(1);
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

（7）mysql> rename table customers to customers_info;
Query OK, 0 rows affected (0.00 sec)

（8）mysql> alter table customers_info drop c_city;
Query OK, 0 rows affected (0.02 sec)
Records: 0  Duplicates: 0  Warnings: 0

（9）mysql> alter table customers_info engine=MyISAM;
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

2、在Market中创建数据表orders。

（1）mysql> create table orders(
    -> o_num int(11) primary key auto_increment,
    -> o_date date,
    -> c_id int(11),
    -> foreign key(c_id) references customers_info(c_num));
Query OK, 0 rows affected (0.01 sec)
注意：MySQL 的 InnoDB 表引擎才支持外键关联，MyISAM 不支持。

        InnoDB，关联键的字段类型要相同（√）

        MyISAM，关联键的字段类型可不同（？）

        *表结构创建好后，添加外键：

        ALTER TABLE orders ADD CONSTRAINT 外键约束名 FOREIGN KEY(c_id) REFERENCES customers_info(c_num);

（2）mysql> alter table orders drop foreign key orders_ibfk_1;
Query OK, 0 rows affected (0.00 sec)
Records: 0  Duplicates: 0  Warnings: 0

        *创建关联字段没有指定外键约束名，将生成一个默认外键约束名，查看：show create table orders;

mysql> drop table customers_info;
Query OK, 0 rows affected (0.01 sec)

3、创建数据库Team，定义数据表player。

（1）          *同时设置密码长度和密码策略

①mysql> create user account1@localhost identified by 'oldpwd1';
Query OK, 0 rows affected (0.00 sec)

mysql> grant select,insert,update(info)  on Team.player from  account1@localhost；
Query OK, 0 rows affected, 1 warning (0.00 sec)

②mysql> grant select,insert,update(info) on Team.player to account1@localhost identified by 'oldpwd1';
Query OK, 0 rows affected, 1 warning (0.00 sec)

（2）mysql>  set password for account1@localhost = password('newpwd2');
Query OK, 0 rows affected, 1 warning (0.00 sec)

（3）mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
（4）mysql> show grants for account1@localhost;
+----------------------------------------------------------------------------------+
| Grants for account1@localhost                                                    |
+----------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'account1'@'localhost'                                     |
| GRANT SELECT, INSERT, UPDATE (info) ON `Team`.`player` TO 'account1'@'localhost' |
+----------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

（5）mysql> revoke select,insert,update(info) on Team.player from account1@localhost;
Query OK, 0 rows affected (0.00 sec)

（6）mysql> drop user account1@localhost;
Query OK, 0 rows affected (0.00 sec)

关联表例子：