データベースのCURD操作

1)SQL 4   :
	(1)DDL(Data Definition Language       ):           :   、 、 
		create drop alter
 
	(2)DML(Data Manipulation Language       ):                
		insert delete update
 
	(3)DQL(Data Query Language        ):             (  )
		select where
 
	(4)DCL(Data Control Language       ):                  ,      
		grant revoke
 
2)DDL:     、 
	(1)     :CRUD
		1.C: Create    
			     : create database db1;
			          : create database if not exists db1;
			          : create database db3 character set gbk;
			        ,          : create database if not exists db1 character set gbk;
 
		2.R: Retrieve   
			         ： show database2;
			            : show create database db1;
 
		3.U: Update   
			    : alter database db3 character set utf8;
 
		4.D: Delete   
			     (      ): drop database db3; 
			            : drop database if exists db3; 
 
		5.     (      ,        (         ))
			            : select database();
			     : use db3;
 
	(2)mysql         
		information_schema: 	
			          、      ;	
			      ,           ;
 
		mysql:
			mysql       
 
		performance_schema：
			            
 
		test:
			           ,        ，