Delete Documents in Collection in MongoDB

Delete Documents in Collection in MongoDB

MongoDB is a popular NoSQL database that allows the storage and retrieval of JSON-like documents. Deleting documents from a collection in MongoDB can be achieved using various methods, depending on the specific requirements. In this documentation, we'll cover two common ways to delete documents in MongoDB using the MongoDB Node.js driver as an example.

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Requirements:

1. Node.js installed on your system.
2. MongoDB Node.js driver (npm package: mongodb).

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Method 1: Deleting a Single Document

Step 1: Installation

Before you begin, make sure you have Node.js installed. If not, download and install Node.js from https://nodejs.org/.

Next, initialize a new Node.js project and install the MongoDB Node.js driver.

bash
mkdir mongodb-delete-example
cd mongodb-delete-example
npm init -y
npm install mongodb

Step 2: Connect to MongoDB

Create a JavaScript file (e.g., app.js) and add the following code to connect to your MongoDB cluster.

javascript
const { MongoClient } = require('mongodb');

const uri = 'mongodb://your_mongodb_connection_string';
const client = new MongoClient(uri);

async function main() {
  try {
    await client.connect();
    console.log('Connected to MongoDB successfully');
  } catch (error) {
    console.error('Error connecting to MongoDB:', error);
  } finally {
    // Ensure the connection is closed after running the example
    await client.close();
  }
}

main();

Replace your_mongodb_connection_string with the actual connection string for your MongoDB cluster.

Step 3: Delete a Document

Now, let's add code to delete a document from a collection.

javascript
const { MongoClient, ObjectId } = require('mongodb');

const uri = 'mongodb://your_mongodb_connection_string';
const client = new MongoClient(uri);

async function main() {
  try {
    await client.connect();
    console.log('Connected to MongoDB successfully');

    const collection = client.db('your_database_name').collection('your_collection_name');
    const deleteResult = await collection.deleteOne({ _id: ObjectId('your_document_id') });

    console.log('Document deleted:', deleteResult.deletedCount === 1);
  } catch (error) {
    console.error('Error:', error);
  } finally {
    await client.close();
  }
}

main();

Replace your_database_name with the name of your MongoDB database and your_collection_name with the name of the collection you want to delete from. Also, set your_document_id to the _id of the document you want to delete.

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Method 2: Deleting Multiple Documents

The following method demonstrates how to delete multiple documents that match a specific condition.

Step 1: Installation

Ensure you have set up the project as shown in Method 1.

Step 2: Connect to MongoDB

Use the same code as shown in Method 1, Step 2 to connect to MongoDB.

Step 3: Delete Multiple Documents

Add the following code to delete multiple documents.

javascript
const { MongoClient } = require('mongodb');

const uri = 'mongodb://your_mongodb_connection_string';
const client = new MongoClient(uri);

async function main() {
  try {
    await client.connect();
    console.log('Connected to MongoDB successfully');

    const collection = client.db('your_database_name').collection('your_collection_name');
    const deleteResult = await collection.deleteMany({ age: { $gte: 30 } });

    console.log(`${deleteResult.deletedCount} documents deleted`);
  } catch (error) {
    console.error('Error:', error);
  } finally {
    await client.close();
  }
}

main();

Replace your_database_name with the name of your MongoDB database and your_collection_name with the name of the collection you want to delete from. In this example, documents with an age greater than or equal to 30 will be deleted.

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Conclusion:

This documentation covered two methods to delete documents in a MongoDB collection using Node.js. Method 1 deletes a single document based on its _id, while Method 2 deletes multiple documents based on a specified condition. You can choose the appropriate method based on your application's requirements. Make sure to handle connections and errors properly in your production-ready applications.

Remember to replace the placeholders (your_mongodb_connection_string, your_database_name, your_collection_name, your_document_id) with actual values specific to your MongoDB deployment.