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Using Mongoose with MongoDB in Node.js

Using Mongoose with MongoDB in Node.js involves several key steps to set up and interact with your database.
1. Project Setup and Installation:
  • Initialize a Node.js project: npm init -y
  • Install Mongoose: npm install mongoose
2. Connecting to MongoDB:
  • Require Mongoose in your application.
  • Use mongoose.connect() to establish a connection, providing your MongoDB connection URI (e.g., mongodb://localhost:27017/yourDatabaseName for local or a connection string from MongoDB Atlas).
  • Handle connection success and error events.
JavaScript

const mongoose = require('mongoose');

const connectDB = async () => {
  try {
    await mongoose.connect('mongodb://localhost:27017/yourDatabaseName', {
      useNewUrlParser: true,
      useUnifiedTopology: true, // Recommended for newer versions
    });
    console.log('MongoDB Connected...');
  } catch (err) {
    console.error(err.message);
    process.exit(1); // Exit process with failure
  }
};

module.exports = connectDB;
3. Defining Schemas and Models:
  • Create a Mongoose Schema to define the structure and types of your data.
  • Create a Mongoose Model from the Schema, which represents a collection in MongoDB and provides an interface for interacting with documents.
JavaScript

const mongoose = require('mongoose');

const userSchema = new mongoose.Schema({
  name: {
    type: String,
    required: true,
  },
  email: {
    type: String,
    required: true,
    unique: true,
  },
  age: Number,
});

const User = mongoose.model('User', userSchema);
module.exports = User;
4. Performing CRUD Operations:
  • Create: 
    Use Model.create() or new Model().save() to insert new documents.
  • Read: 
    Use Model.find() to retrieve multiple documents, Model.findOne() to retrieve a single document, or Model.findById() to find by ID.
  • Update: 
    Use Model.updateOne(), Model.updateMany(), or Model.findByIdAndUpdate() to modify existing documents.
  • Delete: 
    Use Model.deleteOne(), Model.deleteMany(), or Model.findByIdAndDelete() to remove documents.
JavaScript

const User = require('./models/User'); // Assuming User model is in ./models/User.js

// Example: Creating a new user
const newUser = await User.create({ name: 'John Doe', email: 'john@example.com', age: 30 });

// Example: Finding all users
const users = await User.find();

// Example: Updating a user
await User.updateOne({ email: 'john@example.com' }, { age: 31 });

// Example: Deleting a user
await User.deleteOne({ email: 'john@example.com' });
5. Disconnecting from MongoDB (Optional but Recommended):
  • Close the MongoDB connection when your application is shutting down gracefully.
JavaScript

mongoose.connection.close(() => {
  console.log('Disconnected from MongoDB');
});

 

https://www.topcoder.com/thrive/articles/how-to-connect-mongodb-to-node-js-using-mongoose

 

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