MySQL—— Database creation and management

1、 Create database

CREATE DATABASE Statement is used to create a new SQL database .

Syntax and extension

--  Create directly 
CREATE DATABASE database_name;
--  Create a database and specify the character set 
CREATE DATABASE database_name character set 'gbk';
--  If it does not exist, the creation is successful , If it already exists, the creation is unsuccessful , But there is no error 
CREATE DATABASE if NOT exists database_name character set 'utf-8';
--  View the structure of the created database 
show create database database_name

Database name (database_name) In the same RDBMS It has to be the only one .

Create a database instance

CREATE DATABASE mytestdb;

2、 Using a database

If SQL There are multiple databases in the schema , So before starting the operation , You need to select a database that will perform the operation .

USE Statement is used to select any existing database in the user .

grammar ：

--  Currently connected to an existing database 
show database
--  Specify the database to use 
USE database_name;
--  View currently used databases 
select database()

3、 Delete database

DROP DATABASE Statement is used to delete the existing database in the user .

grammar

DROP DATABASE if exists database_name;

If you want to delete an existing database mytestdb, be DROP DATABASE The statement is as follows -

DROP DATABASE if exists mytestdb;

Be careful Be careful before using this operation , Because deleting an existing database will delete the complete information stored in this database , such as ： surface , function , Views and so on will be deleted together .