**Course Title:** Mastering Node.js: Building Scalable Web Applications **Section Title:** Managing Data with MongoDB and Mongoose **Topic:** Performing CRUD operations with Mongoose **Overview** In this topic, we will explore how to perform Create, Read, Update, and Delete (CRUD) operations using Mongoose, a popular Object Data Modeling (ODM) library for MongoDB and Node.js. We will cover the basics of CRUD operations, including how to create, read, update, and delete documents in a MongoDB database using Mongoose. **Prerequisites** Before diving into this topic, make sure you have a basic understanding of: * Node.js and its ecosystem * MongoDB and its data model * Mongoose and its features * Setting up a MongoDB and Mongoose in Node.js **What are CRUD Operations?** CRUD operations are the basic operations that can be performed on data in a database. They are: * **Create**: Create a new document in the database * **Read**: Retrieve a document from the database * **Update**: Update an existing document in the database * **Delete**: Delete a document from the database **Performing CRUD Operations with Mongoose** Mongoose provides a simple and intuitive API for performing CRUD operations on MongoDB documents. Here are some examples of how to perform CRUD operations using Mongoose: ### Create To create a new document in the database, you can use the `create()` method on a Mongoose model. Here is an example: ```javascript const mongoose = require('mongoose'); const userSchema = new mongoose.Schema({ name: String, email: String }); const User = mongoose.model('User', userSchema); const user = new User({ name: 'John Doe', email: 'john.doe@example.com' }); user.save((err, user) => { if (err) { console.error(err); } else { console.log(user); } }); ``` ### Read To retrieve a document from the database, you can use the `find()` method on a Mongoose model. Here is an example: ```javascript const mongoose = require('mongoose'); const userSchema = new mongoose.Schema({ name: String, email: String }); const User = mongoose.model('User', userSchema); User.find({ name: 'John Doe' }, (err, users) => { if (err) { console.error(err); } else { console.log(users); } }); ``` ### Update To update an existing document in the database, you can use the `update()` method on a Mongoose model. Here is an example: ```javascript const mongoose = require('mongoose'); const userSchema = new mongoose.Schema({ name: String, email: String }); const User = mongoose.model('User', userSchema); User.update({ name: 'John Doe' }, { $set: { email: 'john.doe2@example.com' } }, (err, user) => { if (err) { console.error(err); } else { console.log(user); } }); ``` ### Delete To delete a document from the database, you can use the `remove()` method on a Mongoose model. Here is an example: ```javascript const mongoose = require('mongoose'); const userSchema = new mongoose.Schema({ name: String, email: String }); const User = mongoose.model('User', userSchema); User.remove({ name: 'John Doe' }, (err, user) => { if (err) { console.error(err); } else { console.log(user); } }); ``` **Conclusion** In this topic, we covered the basics of CRUD operations using Mongoose. We learned how to create, read, update, and delete documents in a MongoDB database using Mongoose. We also saw some examples of how to perform CRUD operations using Mongoose. **What's Next?** In the next topic, we will explore the principles of RESTful architecture and how to build RESTful APIs using Node.js and Express.js. **Leave a comment or ask for help if you have any questions or need further clarification on any of the concepts covered in this topic.** **External Resources:** * Mongoose documentation: <https://mongoosejs.com/docs/> * MongoDB documentation: <https://docs.mongodb.com/> * Node.js documentation: <https://nodejs.org/docs/> **Practice Exercise:** Create a Mongoose model for a `Book` document with the following schema: ```javascript const bookSchema = new mongoose.Schema({ title: String, author: String, publicationDate: Date }); ``` Then, perform the following CRUD operations using the `Book` model: * Create a new `Book` document with the title "The Great Gatsby" and author "F. Scott Fitzgerald". * Retrieve all `Book` documents with the title "The Great Gatsby". * Update the publication date of the `Book` document with the title "The Great Gatsby" to 1925. * Delete the `Book` document with the title "The Great Gatsby" title.

const mongoose = require('mongoose');
const userSchema = new mongoose.Schema({
  name: String,
  email: String
});
const User = mongoose.model('User', userSchema);

const user = new User({ name: 'John Doe', email: 'john.doe@example.com' });
user.save((err, user) => {
  if (err) {
    console.error(err);
  } else {
    console.log(user);
  }
});

const mongoose = require('mongoose');
const userSchema = new mongoose.Schema({
  name: String,
  email: String
});
const User = mongoose.model('User', userSchema);

User.find({ name: 'John Doe' }, (err, users) => {
  if (err) {
    console.error(err);
  } else {
    console.log(users);
  }
});

const mongoose = require('mongoose');
const userSchema = new mongoose.Schema({
  name: String,
  email: String
});
const User = mongoose.model('User', userSchema);

User.update({ name: 'John Doe' }, { $set: { email: 'john.doe2@example.com' } }, (err, user) => {
  if (err) {
    console.error(err);
  } else {
    console.log(user);
  }
});

const mongoose = require('mongoose');
const userSchema = new mongoose.Schema({
  name: String,
  email: String
});
const User = mongoose.model('User', userSchema);

User.remove({ name: 'John Doe' }, (err, user) => {
  if (err) {
    console.error(err);
  } else {
    console.log(user);
  }
});

const bookSchema = new mongoose.Schema({
  title: String,
  author: String,
  publicationDate: Date
});