1、创建数据库

CREATE DATABASE|SCHEMA [IF NOT EXISTS] 'DB_NAME'
CHARACTER SET 'character set name'
COLLATE 'collate name'; 

# 范例
mysql> create database db1;
Query OK, 1 row affected (0.00 sec)

mysql> show create database db1;
+----------+----------------------------------------------------------------+
| Database | Create Database                                                |
+----------+----------------------------------------------------------------+
| db1      | CREATE DATABASE `db1` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+----------------------------------------------------------------+
1 row in set (0.00 sec)

[root@centos79-mysql01 ~]# cat /data/mysql/db1/db.opt
default-character-set=latin1
default-collation=latin1_swedish_ci

mysql> create database db1;
ERROR 1007 (HY000): Can't create database 'db1'; database exists
mysql> show warnings;
+-------+------+----------------------------------------------+
| Level | Code | Message                                      |
+-------+------+----------------------------------------------+
| Error | 1007 | Can't create database 'db1'; database exists |
+-------+------+----------------------------------------------+
1 row in set (0.00 sec)

# 指定字符集创建新数据库
mysql> create database if not exists db2 character set 'utf8';
Query OK, 1 row affected (0.00 sec)

mysql> create database  db3 character set 'utf8';
Query OK, 1 row affected (0.00 sec)

mysql> show create database db3;
+----------+--------------------------------------------------------------+
| Database | Create Database                                              |
+----------+--------------------------------------------------------------+
| db3      | CREATE DATABASE `db3` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+--------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> show create database db2;
+----------+--------------------------------------------------------------+
| Database | Create Database                                              |
+----------+--------------------------------------------------------------+
| db2      | CREATE DATABASE `db2` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+--------------------------------------------------------------+
1 row in set (0.00 sec)

[root@centos79-mysql01 ~]# cat /data/mysql/db2/db.opt
default-character-set=utf8
default-collation=utf8_general_ci
[root@centos79-mysql01 ~]# cat /data/mysql/db3/db.opt
default-character-set=utf8
default-collation=utf8_general_ci

2、修改数据库

ALTER DATABASE DB_NAME character set utf8;

# 范例
# 修改db1字符集
mysql> alter database db1 character set utf8 collate utf8_bin;
Query OK, 1 row affected (0.00 sec)

mysql> show create database db1;
+----------+-------------------------------------------------------------------------------+
| Database | Create Database                                                               |
+----------+-------------------------------------------------------------------------------+
| db1      | CREATE DATABASE `db1` /*!40100 DEFAULT CHARACTER SET utf8 COLLATE utf8_bin */ |
+----------+-------------------------------------------------------------------------------+
1 row in set (0.00 sec)

[root@centos79-mysql01 ~]# cat /data/mysql/db1/db.opt
default-character-set=utf8
default-collation=utf8_bin

3、删除数据库

DROP DATABASE|SCHEMA [IF EXISTS] 'DB_NAME'; 

# 范例
mysql> drop database db3;
Query OK, 0 rows affected (0.00 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db1                |
| db2                |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
6 rows in set (0.00 sec)

mysql> drop database db2;
Query OK, 0 rows affected (0.00 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db1                |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.00 sec)