DDL : Data Definition Language 用途: 用于描述数据库中存储的现实世界实体的语言。即创建数据库和表的结构。 CREATE ALTER DROP TRUNCATE CREATE {DATABASE | SCHEMA } [ IF NOT EXISTS ] 数据库名称 CREATE DATABASE IF NOT EXISTS mydb3 CHARACTER SET utf8 COLLATE utf8_general_ci; mysql> SHOW CREATE DATABASE mydb1; +----------+----------------------------------------------------------------+ | Database | Create Database | +----------+----------------------------------------------------------------+ | mydb1 | CREATE DATABASE `mydb1` /*!40100 DEFAULT CHARACTER SET utf8 */ | +----------+----------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> mysql> mysql> mysql> mysql> SHOW CREATE DATABASE mydb2; +----------+---------------------------------------------------------------+ | Database | Create Database | +----------+---------------------------------------------------------------+ | mydb2 | CREATE DATABASE `mydb2` /*!40100 DEFAULT CHARACTER SET gbk */ | +----------+---------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> SHOW CREATE DATABASE mydb3; +----------+----------------------------------------------------------------+ | Database | Create Database | +----------+----------------------------------------------------------------+ | mydb3 | CREATE DATABASE `mydb3` /*!40100 DEFAULT CHARACTER SET utf8 */ | +----------+----------------------------------------------------------------+ 1 row in set (0.00 sec) 查询 SHOW DATABASES; SHOW CREATE DATABASE 数据库名称; 删除 DROP DATABASE 数据库名称; mysql> SHOW CREATE DATABASE mydb3; +----------+----------------------------------------------------------------+ | Database | Create Database | +----------+----------------------------------------------------------------+ | mydb3 | CREATE DATABASE `mydb3` /*!40100 DEFAULT CHARACTER SET utf8 */ | +----------+----------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> DROP DATABASE IF EXISTS mydb3; Query OK, 0 rows affected (0.02 sec) mysql> SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | mydb1 | | mydb2 | | mysql | | test | +--------------------+ 5 rows in set (0.00 sec) 修改 ALERT mysql> SHOW CREATE DATABASE mydb1; +----------+----------------------------------------------------------------+ | Database | Create Database | +----------+----------------------------------------------------------------+ | mydb1 | CREATE DATABASE `mydb1` /*!40100 DEFAULT CHARACTER SET utf8 */ | +----------+----------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> ALTER DATABASE mydb2 CHARACTER SET utf8; Query OK, 1 row affected (0.00 sec) mysql> SHOW CREATE DATABASE mydb2; +----------+----------------------------------------------------------------+ | Database | Create Database | +----------+----------------------------------------------------------------+ | mydb2 | CREATE DATABASE `mydb2` /*!40100 DEFAULT CHARACTER SET utf8 */ | +----------+----------------------------------------------------------------+ 1 row in set (0.00 sec) |
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