MongoDB

Overview

MongoDB is the premier document-oriented NoSQL database, offering horizontal scalability, flexible schema design, and high performance for unstructured or semi-structured data. This checklist covers core MongoDB fundamentals, CRUD operations, aggregation pipelines, indexing strategies, and integration with Spring Boot via Spring Data MongoDB.

Tip: Practice writing queries both in MongoDB Compass / Shell and within Spring Data repositories using MongoRepository and MongoTemplate.

MongoDB Fundamentals

• Document model — JSON/BSON, collections, documents
• MongoDB vs SQL — when to use NoSQL
• Install locally / use MongoDB Atlas (cloud)
• MongoDB Shell & Compass GUI

CRUD Operations

• insertOne, insertMany
• find, findOne — query operators: $eq, $gt, $lt, $gte, $lte, $ne
• $in, $nin, $and, $or, $not, $regex
• Projection — include/exclude fields
• updateOne, updateMany — $set, $unset, $push, $pull, $inc, $addToSet
• deleteOne, deleteMany
• sort, limit, skip

Aggregation Pipeline

• $match, $group, $sort, $project, $limit
• $lookup — join equivalent
• $unwind, $addFields, $count
• Accumulator operators — $sum, $avg, $max, $min, $first

Schema Design & Indexing

• Embedding vs referencing — when to use which
• One-to-one, one-to-many, many-to-many patterns
• Indexes — single field, compound, text, unique
• explain() — query performance analysis

Spring Data MongoDB

• @Document, @Field, @Id
• MongoRepository — CRUD methods
• MongoTemplate — complex queries
• @DBRef — referencing documents