mysql数据库的操作

mysql 语句的规范

关键字与函数名称全部大写
数据库名称、表名称、字段名称全部小写
sql语句必须以分号结尾

数据库操作

1 创建数据库

大括号参数必须写，中括号参数可写可不写
CREATE {DTABASE | SCHEMA} [IF NOT EXISTS] db_name
[DEFAULT] CHARACTER SET [=] charset_name

mysql> create database `test`;创建数据库
Query OK, 1 row affected (0.00 sec)

mysql> CREATE DATABASE `test`;	`test`数据库已经存在，再次创建数据库报错
ERROR 1007 (HY000): Can't create database 'test'; database exists
mysql> CREATE DATABASE IF NOT EXISTS`test`;
Query OK, 1 row affected, 1 warning (0.01 sec)

加上	IF NOT EXISTS  判断条件之后就不会error,但是会提示warning()
mysql> CREATE DATABASE IF NOT EXISTS `test`;
Query OK, 1 row affected, 1 warning (0.00 sec)

2 查看创建数据库时的命令

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



3 创建数据库的时候并设置编码格式

mysql> CREATE DATABASE `test1` character set = gbk;
Query OK, 1 row affected (0.00 sec)

mysql> SHOW CREATE DATABASE `test1`;
+----------+---------------------------------------------------------------+
| Database | Create Database                                               |
+----------+---------------------------------------------------------------+
| test1    | CREATE DATABASE `test1` /*!40100 DEFAULT CHARACTER SET gbk */ |
+----------+---------------------------------------------------------------+
1 row in set (0.00 sec)

4 修改数据库的编码方式

ALTER {DATABASE | SCHEMA} [db_name]
[DEFAULT] CHARACTER SET [=] charset_name

mysql> ALTER DATABASE `test1` CHARACTER SET = utf8;
Query OK, 1 row affected (0.00 sec)

5 删除数据库
DROP {DATABASE | SCHEMA} [IF EXISTS] db_name

mysql> DROP DATABASE `test1`;
Query OK, 0 rows affected (0.08 sec)

查看服务器下有哪些数据库
SHOW DATABASES;