Basic concept of database, installation and configuration of database, basic use of MySQL, operation of database in the project

 

（ One ） Basic concepts of database

One 、 What is a database

  Two 、 Common databases and classifications

  3、 ... and 、 The data organization structure of traditional database

 1、Excle The organization of data

2、 The data organization structure of traditional database

 3、 Library in actual development 、 surface 、 That's ok 、 Field relationship

 （ Two ） Install and configure MySQL

One 、 Know what needs to be installed MySQL Related software

 

Two 、MySQL stay Mac Installation in environment

3、 ... and 、MySQL stay Windows Installation in environment

 （ 3、 ... and ）MySQL Basic use of

One 、 Use MySQL Workbench Management database

1、 Connect database

2、 Understand the components of the main interface

 

 3、 Create database

 4、 Create data table

5、 Write data to the table

  Two 、 Use SQL Management database

１、 What is? SQL

　 ２、SQL What can be done

 

  ３、SQL Learning objectives of

  3、 ... and 、SQL Of SELECT sentence

１、 grammar

２、SELECT＊　 Example  

 ３、SELECT Column name 　 Example

 

  Four 、SQL Of INSERT INTO sentence

1、 grammar

2、INSERT INTO Example

 

  5、 ... and 、SQL Of UPDATE sentence

1、 grammar

2、UPDATE An example of

 

 

6、 ... and 、SQL Of DELETE sentence

1、 grammar

2、DELETE  An example of

 

  7、 ... and 、SQL Of WHERE Clause

1、 grammar

2、 Can be found in WHERE Operators used in Clauses

 

 3、WHERE Example of clause

 

  8、 ... and 、SQL Of AND and OR Operator

1、 grammar

2、AND Operator example  

3、OR Operator example

 

  Nine 、SQL Of ORDER BY Clause

1、 grammar

 2、 ORDER BY Clause —— Ascending sort

 3、 ORDER BY Clause —— null

 

 4、ORDER BY Clause —— Multiple sort

 

  Ten 、SQL Of COUNT（*） function

1、 grammar

 2、 COUNT（*） Example

 

3、 Use AS Set an alias for the column

 

 

 （ Four ） Operate in the project MySQL

One 、 Steps to operate a database in a project

  Two 、 Installation and configuration mysql modular

1、 install mysql modular

 2、 To configure mysql modular  

// 1. Import database module 
const mysql = require('mysql')

// 2. Establishment and MySQL  The connection relationship of the database 
const db = mysql.createPool({
    host: '127.0.0.1' ,     // Database IP Address 
    user : 'root',     // Login database account 
    password : 'admin123' ,     // Password to log in to the database 
    database: 'my_db_01'       // Specify which database to operate on 
})

 

3、 test mysql Whether the module can work properly

 

//  test mysql  Whether the module can work properly 
db.query('select 1' , (err , results) => {
    // mysql   An error is reported during module operation 
    if(err) return console.log(err.message);
    //  Be able to successfully execute  SQL sentence 
    console.log(results);
})

3、 ... and 、 Use mysql Module operation MySQL database

1、 Query data

//  Inquire about  users All the data in the table 
const sqlStr = 'select * from users'
db.query(sqlStr , (err , results) => {
    //  Failed to query data 
    if(err) return console.log(err.message);
    //  Query data successful 
    //  Be careful ：  If the execution is  select  Query statement , The result of execution is an array 
    console.log(results);
}) 

2、 insert data

//  insert data 
// 1. towards users In the table , Add a piece of data , among username The value of is Spider-Man,password The value of is pcc123
//  To insert into  users Data objects in the table 
const  user = {username :'Spider-Man' , password : 'pcc123'}
// 2. Define what to do  SQL sentence 
const sqlStr = 'insert into users (username , password) values (? , ?)'
// 3. perform  SQL sentence 
db.query(sqlStr , [user.username , user.password] , (err ,results) => {
    //  perform  SQL Statement failure 
    if(err) return console.log(err.message);
    //  perform  SQL Statement success 
    //  Be careful ：  If the execution is  insert into  Insert statement , be  results It's an object 
    //  Sure   adopt  affectedRows  attribute , To determine whether the data is successfully inserted 
   if(results.affectedRows === 1){
       console.log(' Insert data succeeded ！');
   }
})

 3、 Insert data Convenient way

 

//  Demonstrate a convenient way to insert data 
const  user = {username :'Spider-Man' , password : 'pcc123'}
//  2. Define what to do  SQL sentence 
const sqlStr = 'insert into users set ?'
//  3. perform  SQL sentence 
db.query(sqlStr , [user.username , user.password] , (err ,results) => {
        //  perform  SQL Statement failure 
        if(err) return console.log(err.message);
        //  perform  SQL Statement success 
        //  Be careful ：  If the execution is  insert into  Insert statement , be  results It's an object 
        //  Sure   adopt  affectedRows  attribute , To determine whether the data is successfully inserted 
       if(results.affectedRows === 1){
           console.log(' Insert data succeeded ！');
       }
    })

4、 Update data

//  Update data 
const  user = {id : 6 ,username :'aaa' , password : '111'}
//  2. Definition SQL sentence 
const  sqlStr = 'update users set username=? , password=? where id=?'
//  perform SQL sentence 
db.query(sqlStr, [user.username , user.password , user.id] , (err , results) => {
    if(err) return console.log(err.message);
    //  Be careful ：  Yes  update  After statement ,  The result of execution is also an object , Can pass  affectedRows  Judge whether the update is successful 
    if(results.affectedRows === 1) console.log(' Update data successful ！');
})

 

5、 A convenient way to update data

//  Demonstrate a convenient way to update data 
const  user = {id : 6 ,username :'aaa' , password : '111'}
//  2. Definition SQL sentence 
const  sqlStr = 'update users set ? where id=?'
//  perform SQL sentence 
db.query(sqlStr, [user , user.id] , (err , results) => {
    if(err) return console.log(err.message);
    //  Be careful ：  Yes  update  After statement ,  The result of execution is also an object , Can pass  affectedRows  Judge whether the update is successful 
    if(results.affectedRows === 1) console.log(' Update data successful ！');
})

6、 Delete data

 

//  Delete data 
//  Delete  id= 5  Users of 
const sqlStr = 'delete from users where id=?'
 db.query(sqlStr, 5, (err , results) => {
    if(err) return console.log(err.message);
    //  Be careful ：  Yes  delete  After statement ,  The result of execution is also an object , Can pass  affectedRows  Judge whether the deletion is successful 
    if(results.affectedRows === 1) console.log(' Delete data succeeded ！');
})

7、 Mark deletion

 

//  Mark deletion 
const sqlStr = 'update users set status=? where id=?'
db.query(sqlStr , [1,6] , (err,results) => {
    if(err)  return console.log(err.message);
    if(results.affectedRows === 1) {
        console.log(' Tag deleted successfully ');
    }
})