数据库操作DDL

版权声明：17602128911 https://blog.csdn.net/bus_lupe/article/details/88177662

1. 创建数据库（在磁盘上创建一个对应的文件夹）

create database [if not exists] db_name [character_set_xxx]

2. 查看数据库

show databases;	查看数据库的创建方式
show create database db_name; 查看数据库创建方式 

3. 修改数据库

alter database db_name [character set xxx]

4. 删除数据库

drop database [if exists] db_name

5. 使用数据库

切换数据库 use db_name; --注意：进入到某个数据库后没办法再退回之前状态，但可以通过use进行切换
查看当前使用的数据库 select database();

查看数据库

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sakila             |
| test               |
| world              |
+--------------------+

创建数据库

mysql> create database if not exists lupe;
Query OK, 1 row affected (0.00 sec)

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

删除数据库

mysql> drop database lupe;
Query OK, 0 rows affected (0.01 sec)

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

设置编码格式，显示数据库创建信息

mysql> create database if not exists bibi character set gbk;
Query OK, 1 row affected (0.01 sec)

mysql> show create database bibi;
+----------+--------------------------------------------------------------+
| Database | Create Database                                              |
+----------+--------------------------------------------------------------+
| bibi     | CREATE DATABASE `bibi` /*!40100 DEFAULT CHARACTER SET gbk */ |
+----------+--------------------------------------------------------------+
1 row in set (0.00 sec)

修改数据库信息

mysql> alter database bibi character set utf8;
Query OK, 1 row affected (0.00 sec)

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

使用数据库，查看当前使用数据库

mysql> use bibi;
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| bibi       |
+------------+
1 row in set (0.00 sec)