MySQL overview

brief introduction

MySQL It's a Relational database management system , The Swedish MySQL AB Companies to develop , Belong to Oracle Its products .MySQL Is one of the most popular relational database management systems , stay WEB Application aspect ,MySQL It's the best RDBMS (Relational Database Management System, Relational database management system ) One of the application software .

DB : database （database）： Storing data “ Warehouse ”. It holds a series of organized data .

DBMS: Database management system （Database Management System）. Database is through DBMS gen Build and operate containers .

SQL: Structured query language （Structure Query Language）： A language designed to communicate with a database said .

SQL Language classification

• DML（Data Manipulation Language): Data manipulation statement , For adding Add 、 Delete 、 modify 、 Query database records , And check data integrity
  • INSERT： Add data to the database
  • UPDATE： Modify the data in the database
  • DELETE： Delete data from database
  • SELECT： choice （ Inquire about ） data
• DDL（Data Definition Language): Data definition statement , For libraries and The creation of a table 、 modify 、 Delete .
  • CREATE TABLE： Create database tables
  • ALTER TABLE： Change table structure 、 add to 、 Delete 、 Modify column length
  • DROP TABLE： Delete table
  • CREATE INDEX： Index on a table
  • DROP INDEX： Delete index
• DCL（Data Control Language): Data control statement , Used to define Access rights and security levels of users
  • GRANT： Grant access to
  • REVOKE： Revoke access
  • COMMIT： Commit transaction
  • ROLLBACK： Transaction fallback
  • SAVEPOINT： Set the savepoint
  • LOCK： Lock specific parts of the database

Service startup and shutdown

Open as Administrator cmd window

net start mysql
net stop mysql

Login and exit

Mode one ：

use mysql The command line client comes with （ only root user ）

Mode two ：

mysql -h [ Host name /IP] -P [port] -u [user] -p
mysql -h localhost -P 3306 -u root -p 
 Local users ： mysql -uroot -proot
 Port number default 3306

Common command

MySQL [(none)]> show databases;       #  view the database 
MySQL [(none)]> use test;           #  Use / Open database (test)
MySQL [test]> select database();     #  View the current database 
MySQL [mysql]> show tables;         #  View the tables in the current database 

MySQL [test]> create table stuinfo(   #  Create table 
    -> id int,                     #  Name   type 
    -> name varchar(20));         

MySQL [test]> desc stuinfo;    #  View table structure 

MySQL [test]> insert into stuinfo (id, name) values(1, 'Tom'); #  insert data 
MySQL [test]> select * from stuinfo;     #  Look at the data in the table 

MySQL [test]> update stuinfo set name="John" where id=1;    #  Modifying data 

MySQL [test]> delete from stuinfo where id=1;   #   Delete data 

MySQL [test]> select version();     #  see mysql edition 
MySQL [test]> exit     #  sign out 
 System command 
C:\WINDOWS\system32>mysql --version
mysql  Ver 15.1 Distrib 10.1.38-MariaDB, for Win64 (AMD64)

C:\WINDOWS\system32>mysql -V
mysql  Ver 15.1 Distrib 10.1.38-MariaDB, for Win64 (AMD64)

Grammatical norms

1. Case insensitive , But it is recommended that keywords be capitalized , Table name 、 Column names in lowercase
2. It's better to end each command with a semicolon
3. Every command is as needed , You can indent Or a new line
4. notes
   • Single-line comments ：# Note text
   • Single-line comments ：-- Note text
   • Multiline comment ：/* Note text */