nodejs connects to mongodb database to implement addition, deletion, modification and query

Preparation

1. Install mongodb through npm command

2. Install mongodb database

CRUD operation

Before this, you should have some understanding of the MongoDB database and some of its add, delete, check and modify commands.

1. Add

var MOngoClient= require("mongodb").MongoClient;
 var DB_URL = "mongodb://localhost:27017/chm";
 
 function insertData(db)
 {
   var devices = db.collection('vip');
   var data = {"name":"node","age":22,"addr":"nb","addTime":new Date()};
   devices.insert(data,function(error, result){
     if(error)
     {
       console.log('Error:'+ error);
     }else{
 
       console.log(result.result.n);
     }
     db.close();
   });
 }
 
  
 MongoClient.connect(DB_URL, function(error, db){
   console.log('Connection successful!');
   insertData(db);
 });

2. Find

var mOngodb= require('mongodb')
 var MOngoClient= require('mongodb').MongoClient;
 var DB_CONN_STR = 'mongodb://localhost:27017/chm';
 
 var selectData = function(db, callback) {
  //Connect to table
  var collection = db.collection('vip');
  //Query data
  var whereStr = {"name":'node'};
  collection.find(whereStr,function(error, cursor){
   cursor.each(function(error,doc){
     if(doc){
       //console.log(doc);
       if (doc.addTime) {
         console.log("addTime: "+doc.addTime);
       }
     }
   });
 
  });
 
 }
 
 MongoClient.connect(DB_CONN_STR, function(err, db) {
  console.log("Connection successful!");
  selectData(db, function(result) {
   console.log(result);
   db.close();
  });
 });

3. Update

var MOngoClient= require("mongodb").MongoClient;
 var DB_URL = "mongodb://localhost:27017/chm";
 
 MongoClient.connect(DB_URL, function(error, db){
   console.log("Connection successful!");
   updateData(db);
 });
 
 function updateData(db)
 {
   var devices = db.collection('vip');
   var whereData = {"name":"node"}
   var updateDat = {$set: {"age":26}}; //If $set is not used, replace the entire data
   devices.update(whereData, updateDat, function(error, result){
     if (error) {
       console.log('Error:'+ error);
     }else{
       console.log(result);
     }
     db.close();
   });
 }

4. Delete

var MOngoClient= require('mongodb').MongoClient;
 var DB_URL = "mongodb://localhost:27017/chm";
 
 MongoClient.connect(DB_URL, function(error, db){
   console.log("Connection successful");
   deleteData(db);
 });
 
 function deleteData(db)
 {
   var devices = db.collection('vip');
   var data = {"name":"node"};
   devices.remove(data, function(error, result){
     if (error) {
       console.log('Error:'+ error);
     }else{
       console.log(result.result.n);
     }
     db.close();
   })
 }

Stored procedures

Create stored procedures in mongodb

All stored procedures are stored in db.system.js, through db. eval(“Stored Procedure ID()”); Call the stored procedure.

Call in code:

var MOngoClient= require("mongodb").MongoClient;
 var DB_URL = "mongodb://localhost:27017/chm";
 
 MongoClient.connect(DB_URL, function(error,db){
   console.log("Connection successful!");
   callProcess(db)
 });
 
 function callProcess(db)
 {
   db.eval("get_vip_count()",function(error, result){
     if (error) {
       console.log(error);
     }else{
       console.log("count:"+result);
     }
     db.close();
   });
 }