Introduction to Python development learning notes master the addition, deletion, modification and query of the concept Library

The point of this section

Master the addition, deletion, modification and query of concept base
The duration of this section needs to be controlled 10 Within minutes

One System database

information_schema： Virtual Library , No disk space , It stores some parameters after the database is started , Such as user table information 、 Column information 、 Permission information 、 Character information, etc
performance_schema： MySQL 5.5 Start adding a database ： Mainly used to collect database server performance parameters , Record various events that occur when processing query requests 、 Lock and so on
mysql： Authorization Library , Main storage system user's permission information
test： MySQL Database system automatically created test database

Two Create database

1 grammar (help create database)

CREATE DATABASE Database name charset utf8;

2 Database naming rules ：

 It can be made of letters 、 Numbers 、 Underline 、＠、＃、＄
Case sensitive
Uniqueness
You can't use keywords like create select
Numbers cannot be used alone
The longest 128 position

3、 ... and Database related operations

 view the database
show databases;
show create database db1;
select database();
Select database
USE Database name
Delete database
DROP DATABASE Database name ;
modify the database
alter database db1 charset utf8;