Mongoose Model.createCollection() API

The Model.createCollection() method of the Mongoose API is used to create a collection for the model. Mongoose by default does not create any collection for the model in the database until any documents are created. The createCollection() method is used to create a collection explicitly.

Setting up Node.js application:

Step 1: Create a Node.js application using the following command:

npm init

Step 2: After creating the NodeJS application, Install the required module using the following command:

npm install mongoose

Project Structure: The project structure will look like this:

Example 1: In this example, We have established a database connection using mongoose and defined model over userSchema. In the end, we are creating a collection on the User model.

• app.js: Write down the below code in the app.js file:

app.js

// Require mongoose module
const mongoose = require('mongoose');

// Set Up the Database connection
mongoose.connect(
    'mongodb://localhost:27017/geeksforgeeks', {
    useNewUrlParser: true,
    useUnifiedTopology: true
})

// Defining User schema
const userSchema = new mongoose.Schema(
    { name: String, age: Number }
)

// Defining User model
const User = mongoose.model('User', userSchema);

// Create collection of Model
User.createCollection().then(function (collection) {
    console.log('Collection is created!');
});

Steps to run the program: To run the application execute the below command from the root directory of the project:

node app.js

Output:

1. On Console:

Collection is created!

2. You can use any GUI tool for the representation of the database in graphical form. Here, I have used the Robo3T GUI tool for graphical representation.

Example 2: In this example, We have established a database connection and added a callback function which will execute once the database connection is established and defined model over userSchema. In the end, we are creating a collection on the User model.

• app.js: Write down the below code in the app.js file:

app.js

// Require the mongoose module
const mongoose = require('mongoose');
const Schema = mongoose.Schema;

// Set Up the Database connection
mongoose.connect('mongodb://localhost:27017/geeksforgeeks', {
    useNewUrlParser: true,
    useUnifiedTopology: true
}).then((result) => {
    console.log('Connection Established')
}).catch((err) => {
    console.log(err)
});

// Defining User schema
const userSchema = new Schema(
    { name: String, age: Number, email: String }
)

// Defining User model
const User = mongoose.model('User', userSchema);

// Create collection of Model
User.createCollection().then(function (collection) {
    console.log('Collection is created!');
});

Steps to run the program: To run the application execute the below command from the root directory of the project:

node app.js

Output:

1. On Console:

Connection Established
Collection is created!

2. You can use any GUI tool for the representation of the database in graphical form. Here, I have used the Robo3T GUI tool for graphical representation.

Reference: https://mongoosejs.com/docs/api/model.html#model_Model-createCollection