Node.js operates the MongoDb database

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1. Use the MongoDb database in Nodejs

Nodejs official document of mongodb database operations

npm install mongodb --save 
/ / or
cnpm install mongodb --save 
/ / or
yarn add mongodb
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/ / into the mongo
const {MongoClient} = require('mongodb');

// Define the address of the database connection
const url = 'mongodb://localhost:27017'; 
// const url = 'mongodb://admin:123456@localhost:27017/'; There is a password connection mode Admin indicates the user name, and 123456 indicates the password

// Define the database to operate on
const dbName = 'itying';

MongoClient.connect(url, { useUnifiedTopology: true },(err,client) = >{
  if(err){
    console.log(err); 
    return; 
  }
  console.log("Connection successful"); 
  // Get the db object
  const db = client.db(dbName); 

  // Close the database when you are done with it
  client.close();
})


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2. Nodejs searches for the MongoDb database data

const {MongoClient} = require('mongodb');
const url = 'mongodb://localhost:27017'; 
// const url = 'mongodb://admin:123456@localhost:27017/'; There is a password connection mode Admin indicates the user name, and 123456 indicates the password
// Define the database to operate on
const dbName = 'itying';

MongoClient.connect(url, { useUnifiedTopology: true },(err,client) = >{
  if(err){
    console.log(err); 
    return; 
  }
  console.log("Connection successful"); 
  // Get the db object
  const db = client.db(dbName); 

  // Find data
  db.collection('user').find({"age":12}).toArray((err,data) = > {
    console.log(data)
    
    // Close the database when you are done with itclient.close(); })})Copy the code

3. Nodejs adds data to MongoDb

const {MongoClient} = require('mongodb');
const url = 'mongodb://localhost:27017'; 
// const url = 'mongodb://admin:123456@localhost:27017/'; There is a password connection mode Admin indicates the user name, and 123456 indicates the password
// Define the database to operate on
const dbName = 'itying';

MongoClient.connect(url, { useUnifiedTopology: true },(err,client) = >{
  if(err){
    console.log(err); 
    return; 
  }
  console.log("Connection successful"); 
  // Get the db object
  const db = client.db(dbName); 

  // Add data
  db.collection('user').insertOne({"name":"Tester"."age":17},(err,result) = >{
    if(err){
      console.log(err);
      return;
    }
    console.log(result);
    client.close()
  })
})
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4. Nodejs Modifies MongoDb data

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017'; 
// const url = 'mongodb://admin:123456@localhost:27017/'; There is a password connection mode Admin indicates the user name, and 123456 indicates the password
// Define the database to operate on
const dbName = 'itying';

MongoClient.connect(url, { useUnifiedTopology: true },(err,client) = >{
  if(err){
    console.log(err); 
    return; 
  }
  console.log("Connection successful"); 
  // Get the db object
  const db = client.db(dbName); 

  // Modify the data
  db.collection('user').updateOne({"name": "xiaoming"}, {$set: {"age": 20}},(err,result) = >{
    if(err){
      console.log(err);
      return;
    }
    console.log(result);
    client.close()
  })
})
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5. Nodejs Deletes MongoDb data

const { MongoClient } = require('mongodb');
const url = 'mongodb://localhost:27017'; 
// const url = 'mongodb://admin:123456@localhost:27017/'; There is a password connection mode Admin indicates the user name, and 123456 indicates the password
// Define the database to operate on
const dbName = 'itying';

MongoClient.connect(url, { useUnifiedTopology: true },(err,client) = >{
  if(err){
    console.log(err); 
    return; 
  }
  console.log("Connection successful"); 
  // Get the db object
  const db = client.db(dbName); 

  // Delete a piece of data
  db.collection('user').deleteOne({"name": "xiaoming"},(err,result) = >{
    if(err){
      console.log(err);
      return;
    }
    console.log(result);
    client.close()
  })
  // Delete multiple pieces of data
  db.collection('user').deleteMany({"name": "Designer"},(err,result) = >{
    if(err){
      console.log(err);
      return;
    }
    console.log(result);
    client.close()
  })
})
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