Mongoose | deleteOne() Function

The deleteOne() function is used to delete the first document that matches the conditions from the collection. It behaves like the remove() function but deletes at most one document regardless of the single option. Installation of mongoose module:

  1. You can visit the link to Install mongoose module. You can install this package by using this command.
npm install mongoose
  1. After installing mongoose module, you can check your mongoose version in command prompt using the command.
npm version mongoose
  1. After that, you can just create a folder and add a file, for example index.js. To run this file you need to run the following command.
node index.js

Filename: index.js 

javascript




const mongoose = require('mongoose');
 
// Database connection
mongoose.connect('mongodb://127.0.0.1:27017/w3wiki', {
    useNewUrlParser: true,
    useCreateIndex: true,
    useUnifiedTopology: true
});
 
// User model
const User = mongoose.model('User', {
    name: { type: String },
    age: { type: Number }
});
 
// Function call
// Delete first document that matches
// the condition i.e age >= 10
User.deleteOne({ age: { $gte: 10 } }).then(function(){
    console.log("Data deleted"); // Success
}).catch(function(error){
    console.log(error); // Failure
});


Steps to run the program:

  1. The project structure will look like this:
  2. Make sure you have installed mongoose module using following command:
npm install mongoose
  1. Below is the sample data in the database before the deleteOne() function is executed, You can use any GUI tool or terminal to see the database, like we have used Robo3T GUI tool as shown below:
  2. Run index.js file using below command:
node index.js
  1. After running above command, you can see the data is deleted from the database.

So this is how you can use the mongoose deleteOne() function to delete the first document that matches the condition from the collection in MongoDB and Node.js.


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