MongoDB Required Constraint using Node.js

Last Updated : 04 Mar, 2021

Mongoose module is one of the most powerful external modules of the node.js.Mongoose is a MongoDB ODM i.e (Object database Modelling) that used to translate the code and its representation from MongoDB to the Node.js server. Mongoose module provides several functions in order to manipulate the documents of the collection of the MongoDB database (Refer this Link)

Required Constraint: This constraint does not allow to skip the value of a particular key in the document of MongoDB collection. This constraint same as a not-null constraint in MySQL.

Installing Module: Install the required module using the following command.

npm install mongoose

Project Structure: Our project structure will look like this.

Running Server on Local IP: Data is the directory where MongoDB server is present.

mongod --dbpath=data --bind_ip 127.0.0.1

index.js

// Importing mongoose module 
const mongoose = require("mongoose") 
  
// Database Address 
const url = "mongodb://localhost:27017/GFG"
  
// Connecting to database 
mongoose.connect(url).then((ans) => { 
  console.log("Connected Successful") 
}).catch((err) => { 
  console.log("Error in the Connection") 
}) 
  
// Calling Schema class 
const Schema = mongoose.Schema; 
  
// Creating Structure of the collection 
const collection_structure = new Schema({ 
  name: { 
    type: String, 
    required: true
  }, 
  marks: { 
    type: Number 
  } 
}) 
  
// Creating collection 
const collections = mongoose.model("GFG2", collection_structure) 
  
// Inserting one document 
collections.create({ 
  // Inserting value of only one key 
  marks: 3 
}).then((ans) => { 
  console.log(ans); 
}).catch((err) => { 
  console.log(err.message); 
})