MySQL基础《一》数据库的命令操作

1、创建数据库

1.1 CREATE {DATABASE|SCHEMA} db_name;

mysql> CREATE DATABASE bingwu;或CREATE SCHEMA bingwu;
Query OK, 1 row affected (0.00 sec)

mysql> SHOW DATABASES;        
+--------------------+
| Database           |
+--------------------+
| bingwu             |

1.2检查数据库是否存在，不存在则创建CREATE DATABASE[IF NOT EXISTS] db_name;

mysql> CREATE DATABASE IF NOT EXISTS bingwu;
Query OK, 1 row affected, 1 warning (0.00 sec)

1.3 创建数据的同时指定编码方式；

CREATE DATABASE [IF NO EXISTS] db_name [DEFAULT] CHARCTER SET [=]  charset;

注意：数据库的名称要有意义；名称不能包含特殊字符或者是MySQL关键字

2、 查看全部数据库 SHOW DATABASES|SCHEMAS;

mysql> SHOW DATABASES;                      
+--------------------+
| Database           |
+--------------------+
| information_schema |
| bingwu             |

3、查看指定的数据库详细信息 SHOW CREATE DATABASE db_name;

mysql> SHOW CREATE DATABASE bingwu;
+----------+-----------------------------------------------------------------+
| Database | Create Database                                                 |
+----------+-----------------------------------------------------------------+
| bingwu   | CREATE DATABASE `bingwu` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+-----------------------------------------------------------------+
1 row in set (0.00 sec)

4、修改指定数据库编码方式  alter database db_name [default] character set [=] charset;

mysql> ALTER DATABASE bingwu DEFAULT CHARACTER SET=utf8; 
Query OK, 1 row affected (0.00 sec)

mysql> 

5、打开指定数据库 use db_name;

mysql> USE bingwu;
Database changed

6、得到当前打开的数据库 select databse()|schema();

mysql> SELECT DATABASE();
+------------+
| DATABASE() |
+------------+
| bingwu     |
+------------+
1 row in set (0.00 sec)

mysql> 

7、删除指定的数据库drop database db_name; 如果数据库存在删除：drop database [if exists] db_name;

mysql> DROP DATABASE bingwu1; 
Query OK, 0 rows affected (0.01 sec)

mysql> DROP DATABASE IF EXISTS bingwu1;# 不存在会有警告
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql>

8、查看警告warning

mysql> show warnings;
+-------+------+-------------------------------------------------------+
| Level | Code | Message                                               |
+-------+------+-------------------------------------------------------+
| Note  | 1008 | Can't drop database 'bingwu1'; database doesn't exist |
+-------+------+-------------------------------------------------------+
1 row in set (0.00 sec)

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