Use of mongodb in node

install mongodb

First of all, let's have a look at this database ,MongoDB Is a database based on distributed file storage . from C++ Language writing . For the purpose of WEB Applications provide scalable, high-performance data storage solutions .
Install and configure this database by referring to the official website ！ This blog mainly explains the relationship between the database and node How to establish a connection and realize the main functions of adding, deleting, modifying and checking ！

install mongoose

We use mongoose This third party package ！

  $ npm install mongoos  

Set the collection structure , The field name is the attribute name in the table structure , The purpose of constraints is to ensure that there is no dirty data ！

var Schema = mongoose.Schema;
var userSchame = new Schema({
    
    username: {
    
        type: String,
        required: true
    },
    age: {
    
        type: Number,
        required: true
    },
    mobelphone: {
    
        type: Number
    }
})

Connect to database , The connection is test database ！

mongoose.connect('mongodb://localhost:27017/test', {
     useNewUrlParser: true });

Publish the document structure as a model ,mongoose The first uppercase string will be used as the name of the database , And take its lowercase string complex number as a set ！

var User = mongoose.model('User', userSchame);

var admin = new User({
    
    username: "gaochi",
   age:18, 
    mobelphone: "12345678"
});

increase

admin.save(function (err, ret) {
    
  if (err) {
    
      console.log("wrong！")
  }
  else {
    
      console.log(ret);
  }
}) 

Delete

 User.remove(
    {
     name: 'renjialei' },
    function (err, ret) {
    
        if (err) {
    
            console.log(" Delete failed ");
        } else {
    
            console.log(" Delete successful ");
        }
    })

Change

User.updateMany({
     username: 'renjialei' }, {
     age: 17 }, function (err, ret) {
    
    if (err) {
    
        console.log(" Change failed ");
    } else {
    
        console.log(" Change succeeded ");
    }
})

check

User.find(
    // Here is our query criteria ！
    /* { username: 'gaochi' }, */
    function (err, ret) {
    
        if (err) {
    
            console.log('err!');
        } else {
    
            console.log(ret);
        }
    })  

Finally, add a few mongodb Simple commands for

mongod   // Open database ！
mongo    // After opening the database , This command can connect the database and the client ！
show dbs   // Show the database collection name 
use （collections）// Enter the database collection , Create if not ！
db.(collections).find()  // Find the data in the collection ！
show collections   // Show all collections in the database ！
db.(collections).insertOne({
    })  // Add data to the database ！

Add a very important knowledge point ,mongod Command can be started mongodb Program , You must create a /data/db Folder , Save our data , Instead of downloading mongodb Create a folder under the directory of ！mongo The command is used in our project file , Connect the project to the database ！