数据库-操作数据库

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mysql>

创建数据库

**创建数据库 无论大小写 都可以创建 那么会有这样创建组合 ：GAME game **
可以是 GaME gaMe 但最后整个效果是 game只认小写 这样的当然创建数据库是为了应用才创建 去使用！当然创建数据库就像一个空仓库 货物，以及 货物 都为空 当然本来空 填充这些货物称之为 表

create database databaseName;

演示:

mysql> create database GAME;
Query OK, 1 row affected (0.01 sec)

查看 当前 所有的数据库

查看所有数据库

包括 数据库系统， 用户自己创建数据库

show databases;

+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sakila             |
| sys                |
| world              |
+--------------------+
6 rows in set (0.01 sec)

选择或者说使用数据库

use  databaseName;

 use game
Database changed
mysql> show tables;
Empty set (0.01 sec)

mysql> use world
Database changed
mysql> show tables;
+-----------------+
| Tables_in_world |
+-----------------+
| city            |
| country         |
| countrylanguage |
+-----------------+
3 rows in set (0.00 sec)

world 是系统简单的示例
作为 一些新手 的练手必备 当然删除这个数据库也没什么 主要是不要把其他的都删了

删除数据库

drop database databaseName;

删除数据库 慎用 无论大写或者小写都 只要能匹配上的数据库名字都能删除
比如说创建一个名Game 的数据库 无论大小写 都可以删除 那么会有这样删除组合 ：GAME game gAme GaMe

mysql> create database Game;
Query OK, 1 row affected (0.15 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| game               |
| information_schema |
| mysql              |
| performance_schema |
| sakila             |
| sys                |
| world              |
+--------------------+
7 rows in set (0.04 sec)
mysql> drop database GAME;
Query OK, 0 rows affected (0.12 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sakila             |
| sys                |
| world              |
+--------------------+
6 rows in set (0.00 sec)
mysql> create database Game;
Query OK, 1 row affected (0.00 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| game               |
| information_schema |
| mysql              |
| performance_schema |
| sakila             |
| sys                |
| world              |
+--------------------+
7 rows in set (0.00 sec)
mysql> create database Game_infor;
Query OK, 1 row affected (0.02 sec)
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| game               |
| game_infor         |
| information_schema |
| mysql              |
| performance_schema |
| sakila             |
| sys                |
| world              |
+--------------------+
8 rows in set (0.00 sec)
mysql> drop database game;
Query OK, 0 rows affected (0.04 sec)
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| game_infor         |
| information_schema |
| mysql              |
| performance_schema |
| sakila             |
| sys                |
| world              |
+--------------------+
7 rows in set (0.00 sec)
mysql> create database  GaMeInfor;
Query OK, 1 row affected (0.01 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| gameinfor          |
| information_schema |
| mysql              |
| performance_schema |
| sakila             |
| sys                |
| world              |
+--------------------+
7 rows in set (0.00 sec)

mysql> drop database GaMe;
ERROR 1008 (HY000): Can't drop database 'game'; database doesn't exist
// 错误1008（HY000）：无法删除数据库“game”；数据库不存在

还以为 删除不明确的 没想到居然 指定的删除 还真是 指定删除库 不过还好这里面没数据

居然创建也是如此 还真得好好的命名数据库名称