一、(dos下)数据库的创建、删除、查看和使用
1.1 普通方式登录后再使用数据库
1 Microsoft Windows [版本 6.1.7601] 2 版权所有 (c) 2009 Microsoft Corporation。保留所有权利。 3 4 C:\Users\Dell>cd c: 5 6 c:\>d: 7 8 D:\>cd D:\Program Files\MySQL\MySQL Server 5.0\bin 9 10 D:\Program Files\MySQL\MySQL Server 5.0\bin>mysql -uroot -p 11 Enter password: **** 12 Welcome to the MySQL monitor. Commands end with ; or \g. 13 Your MySQL connection id is 3 14 Server version: 5.0.45-community-nt MySQL Community Edition (GPL) 15 16 Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the buffer. 17 18 mysql> --1.创建数据库 19 mysql> create database if not exists hollydata; 20 Query OK, 1 row affected (0.05 sec) 21 22 mysql> --2.查看数据库 23 mysql> show databases; 24 +--------------------+ 25 | Database | 26 +--------------------+ 27 | information_schema | 28 | hollydata | 29 | mysql | 30 | test | 31 +--------------------+ 32 4 rows in set (0.00 sec) 33 34 mysql> --3.删除数据库 35 mysql> drop database if exists hollydata; 36 Query OK, 0 rows affected (0.31 sec) 37 38 mysql> --4.查看数据库 39 mysql> show databases; 40 +--------------------+ 41 | Database | 42 +--------------------+ 43 | information_schema | 44 | mysql | 45 | test | 46 +--------------------+ 47 3 rows in set (0.00 sec) 48 49 mysql> --5.使用数据库(也就是数据的切换) 50 mysql> use test 51 Database changed 52 mysql>
数据库的创建、删除、查看、使用
1.2 在登录的时候就选择使用的数据库
登录的时候选择使用的数据库
二、结构化语言分类
三、创建数据库表语法
四、数据库列类型
4.1 数值类型
4.2 字符串类型
4.3 时间类型
4.4 null类型
五、列的属性字段
5.1 创建数据库并使用数据
1 mysql> create database hollydata; 2 Query OK, 1 row affected (0.00 sec) 3 4 mysql> use hollydata; 5 Database changed
创建数据库并使用数据
5.2 创建数据库表students
1 mysql> create table students 2 -> (id int unsigned not null auto_increment primary key, 3 -> name char(8) not null, 4 -> sex char(4) not null, 5 -> age tinyint unsigned not null, 6 -> tel char(13) null default ‘_‘ 7 -> ); 8 Query OK, 0 rows affected (0.45 sec)
创建数据库表students
5.3 查看表结构
1 mysql> desc students; 2 +-------+---------------------+------+-----+---------+----------------+ 3 | Field | Type | Null | Key | Default | Extra | 4 +-------+---------------------+------+-----+---------+----------------+ 5 | id | int(10) unsigned | NO | PRI | NULL | auto_increment | 6 | name | char(8) | NO | | | | 7 | sex | char(4) | NO | | | | 8 | age | tinyint(3) unsigned | NO | | | | 9 | tel | char(13) | YES | | _ | | 10 +-------+---------------------+------+-----+---------+----------------+ 11 5 rows in set (0.08 sec) 12 13 mysql>
查看表结构
六、修改数据库表
6.1 修改表名
1 mysql> alter table students rename as stu; 2 Query OK, 0 rows affected (0.22 sec)
修改数据库表
6.2 查看该数据下所有的数据库表
1 mysql> show tables; 2 +---------------------+ 3 | Tables_in_hollydata | 4 +---------------------+ 5 | stu | 6 +---------------------+ 7 1 row in set (0.00 sec) 8 9 mysql>
显示数据库下的所有数据库表
6.3 添加字段
1 D:\Program Files\MySQL\MySQL Server 5.0\bin>mysql -D hollydata -u root -p 2 Enter password: **** 3 Welcome to the MySQL monitor. Commands end with ; or \g. 4 Your MySQL connection id is 6 5 Server version: 5.0.45-community-nt MySQL Community Edition (GPL) 6 7 Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the buffer. 8 9 mysql> --添加password密码字段 10 mysql> alter table stu add password char(8); 11 Query OK, 0 rows affected (0.32 sec) 12 Records: 0 Duplicates: 0 Warnings: 0 13 14 mysql> --查看表结构 15 mysql> desc stu; 16 +----------+---------------------+------+-----+---------+----------------+ 17 | Field | Type | Null | Key | Default | Extra | 18 +----------+---------------------+------+-----+---------+----------------+ 19 | id | int(10) unsigned | NO | PRI | NULL | auto_increment | 20 | name | char(8) | NO | | | | 21 | sex | char(4) | NO | | | | 22 | age | tinyint(3) unsigned | NO | | | | 23 | tel | char(13) | YES | | _ | | 24 | password | char(8) | YES | | NULL | | 25 +----------+---------------------+------+-----+---------+----------------+ 26 6 rows in set (0.01 sec) 27 28 mysql>
添加字段
6.5 修改字段
1 mysql> --修改password字段 2 mysql> alter table stu modify password char(4); 3 Query OK, 0 rows affected (0.24 sec) 4 Records: 0 Duplicates: 0 Warnings: 0 5 6 mysql> alter table stu change password pwd char(5); 7 Query OK, 0 rows affected (0.23 sec) 8 Records: 0 Duplicates: 0 Warnings: 0 9 10 mysql> --查看表结构 11 mysql> desc stu; 12 +-------+---------------------+------+-----+---------+----------------+ 13 | Field | Type | Null | Key | Default | Extra | 14 +-------+---------------------+------+-----+---------+----------------+ 15 | id | int(10) unsigned | NO | PRI | NULL | auto_increment | 16 | name | char(8) | NO | | | | 17 | sex | char(4) | NO | | | | 18 | age | tinyint(3) unsigned | NO | | | | 19 | tel | char(13) | YES | | _ | | 20 | pwd | char(5) | YES | | NULL | | 21 +-------+---------------------+------+-----+---------+----------------+ 22 6 rows in set (0.01 sec) 23 24 mysql>
修改字段
6.6 删除字段
1 mysql> alter table stu drop pwd; 2 Query OK, 0 rows affected (0.24 sec) 3 Records: 0 Duplicates: 0 Warnings: 0 4 5 mysql> desc stu; 6 +-------+---------------------+------+-----+---------+----------------+ 7 | Field | Type | Null | Key | Default | Extra | 8 +-------+---------------------+------+-----+---------+----------------+ 9 | id | int(10) unsigned | NO | PRI | NULL | auto_increment | 10 | name | char(8) | NO | | | | 11 | sex | char(4) | NO | | | | 12 | age | tinyint(3) unsigned | NO | | | | 13 | tel | char(13) | YES | | _ | | 14 +-------+---------------------+------+-----+---------+----------------+ 15 5 rows in set (0.01 sec) 16 17 mysql>
删除字段
七、删除数据库表
7.1 删除数据库表
1 mysql> drop table if exists stu; 2 Query OK, 0 rows affected (0.07 sec) 3 4 mysql> --查看该库下用户下的所有数据库表 5 mysql> show tables; 6 Empty set (0.00 sec) 7 8 mysql>
删除数据库表
时间: 2024-08-05 11:45:41