The document provides a comprehensive guide to using Mongoose for managing MongoDB through CRUD operations including create, read, update, and delete. It covers installation, schema definition, and the significance of middleware for enhancing database interactions. The emphasis is on Mongoose's ability to simplify MongoDB operations and enforce schema validation.

1. CRUD OPERATION USING MOONGOOSE
A Guide to Managing MongoDB with Mongoose
Soniya [22EC161]
Sree Vishnu Varthini [22EC162]
Sree Nithi [22EC163]
Sri Krishna [22EC164]

2. Agenda
 Introduction
 Setting Up Mongoose
 Defining a Schema
 Create Operation
 Read Operation
 Update Operation
 Delete Operation
 Mongoose Middleware
 Conclusion

3. Introduction to
Mongoose

4. Introduction
•Mongoose is an Object Data Modeling (ODM) library for MongoDB and Node.js.
•Provides a straight-forward, schema-based solution to model your application data.
•Why use Mongoose?
• Schema validation
• Middleware support
• Query building

5. Setting Up Mongoose
Installation:
npm install mongoose
Connecting to MongoDB:

6. Defining a Schema
Example Schema: Creating a Model:
Creating a Model:

7. READ Operation
Description:
Retrieving documents from the collection.
Example:
Finding by ID:

8. Delete Operation
Description:
Removing documents from the collection.
Example:

9. Update Operation
Description:
Modifying existing documents in the collection.
Example:

10. Mongoose Middleware: Pre Hooks
Pre hooks are functions that run before a
specified document operation occurs. They are
often used for validation, modification, or setting
defaults on the document before it gets saved
to the database. The next function must be
called to move to the next middleware or to
complete the operation.
Purpose: To ensure all email addresses are stored in lowercase, facilitating case-
insensitive email lookups.
How it works: Before saving a user document, the email field is converted to
lowercase. The next() function is called to proceed with the save operation.

11. Mongoose Middleware: Post Hooks
Post hooks run after a specified document
operation has completed. They can be used for
logging, sending notifications, or performing
cleanup tasks. Unlike pre hooks, post hooks
have access to the document and the result of
the operation.
Purpose: To log a message every time a new user is created and saved to the
database.
How it works: After a user document is successfully saved, the hook logs a message
along with the saved document (doc). The next() function is called to complete the
process.

12. Conclusion
•Mongoose simplifies interactions with MongoDB through schemas and models.
•CRUD operations (Create, Read, Update, Delete) are essential for database management.
•Middleware provides additional control over database operations.

13. Thank you
Soniya [22EC161]
Sree Vishnu Varthini [22EC162]
Sree Nithi [22EC163]
Sri Krishna[