Mongo DB

Express.js

Express.js is a minimal, unopinionated web application framework for Node.js that provides a lightweight set of features — routing, middleware, and HTTP utilit…

MongoDB

MongoDB is an open-source, document-oriented NoSQL database that stores data as flexible, JSON-like documents (BSON) rather than rows and columns in fixed tabl…

Redis

Redis is an open-source, in-memory data structure store used as a database, cache, and message broker, supporting strings, hashes, lists, sets, and sorted sets…

Firebase

Firebase is Google's mobile and web application development platform, offering a suite of managed backend services including a real-time database, authenticati…

SQLite

SQLite is a lightweight, serverless, self-contained relational database engine that reads and writes directly to a single ordinary disk file, making it one of…

Aerospike

Aerospike is a high-performance, distributed NoSQL database designed for sub-millisecond read/write latency and high throughput at large scale, commonly used i…

CouchDB

Apache CouchDB is an open-source NoSQL document database that stores data as JSON documents and exposes an HTTP/REST API as its primary interface, with built-i…

Algolia

Algolia is a hosted search-as-a-service platform that provides fast, typo-tolerant, full-text search and discovery APIs that developers embed into websites and…

Amazon DynamoDB

Amazon DynamoDB is a fully managed, serverless NoSQL database from AWS that stores data as key-value pairs and documents, designed to deliver consistent, singl…

Appsmith

Appsmith is an open-source low-code platform for quickly building internal tools such as admin panels, dashboards, and CRUD applications by connecting to datab…

ArangoDB

ArangoDB is an open-source native multi-model database that supports graph, document, and key-value data models within a single storage engine, queried through…

Debezium

Debezium is an open-source distributed platform for change data capture (CDC) that captures row-level changes in databases and streams them as event logs, typi…

RethinkDB

RethinkDB is an open-source, distributed NoSQL document database built for real-time applications, letting clients subscribe to live query results ("changefeed…

Mongoose

Mongoose is an Object Data Modeling (ODM) library for Node.js that provides schema definitions, validation, and a structured query API on top of MongoDB.

Apache Cassandra

Apache Cassandra is an open-source, distributed NoSQL wide-column database designed for high write throughput, linear horizontal scalability, and continuous av…

Meteor.js

Meteor.js is a full-stack JavaScript framework that lets developers write both client and server code in one codebase, with built-in real-time data synchroniza…

Apache Drill

Apache Drill is an open-source, schema-free SQL query engine designed for interactive analysis of large-scale datasets across files, NoSQL databases, and cloud…

Sharding

Sharding is a database scaling technique that splits a large dataset horizontally across multiple independent database instances (shards), each holding a subse…

Document Database

A document database stores data as flexible, self-contained documents — typically JSON or BSON — allowing each record to have its own structure without requiri…

PostgreSQL vs Other Databases

Compare PostgreSQL against MySQL, MongoDB, and other popular databases to understand where it excels and where alternatives may fit better.

Aggregation Performance

Learn practical techniques for diagnosing and improving the performance of MongoDB aggregation pipelines, from index usage to explain plans.

BSON vs JSON

How BSON, MongoDB's binary storage format, differs from JSON in type support, size, and parsing performance.

Common Aggregation Stages

A practical tour of the most frequently used aggregation stages — $match, $project, $sort, $limit, $skip, and $unwind — and how they reshape documents.

Compound Indexes

Understand how MongoDB compound indexes combine multiple fields, the ESR rule for ordering keys, and how they support sorting and covered queries.

Data Modeling Patterns

A tour of named MongoDB schema design patterns — attribute, bucket, computed, subset, and extended reference — and the problems each one solves.

Deleting Documents

Learn how to remove documents from MongoDB collections with deleteOne and deleteMany, and how to safely drop entire collections.

Documents and Collections

How MongoDB structures data into documents and collections, including field types, embedding versus referencing, and the _id field.

Embedding vs Referencing

Understand the core MongoDB modeling trade-off between embedding related data inside a document and referencing it via a separate collection.

Grouping and Accumulators

Master the $group stage and its accumulator operators to compute sums, averages, counts, and other summaries across groups of documents.

Indexes in MongoDB

Learn how MongoDB indexes work internally, why they speed up queries, and how to create and manage the core index types.

Inserting Documents

Learn how to add data to MongoDB collections with insertOne and insertMany, how _id is generated, and how schema flexibility affects inserts.

Installing and Connecting to MongoDB

How to install MongoDB locally or run it with Docker, connect using a connection string, and get started with MongoDB Atlas.

$lookup and Joins in MongoDB

Understand how $lookup performs left outer joins across collections in the aggregation pipeline, from simple equality joins to correlated subqueries.

MongoDB Interview Questions

A curated set of commonly asked MongoDB interview questions and concepts, covering data modeling, indexing, replication, and sharding fundamentals.

MongoDB Quick Reference

A fast lookup guide to the most commonly used MongoDB shell commands, operators, and CRUD syntax for day-to-day development.

Performance Tuning Basics

Practical techniques for diagnosing and fixing slow MongoDB queries, covering the profiler, index hygiene, schema design, and working-set memory.

Query Operators

Master MongoDB's comparison, logical, element, and array query operators like $gt, $in, $and, $exists, and $elemMatch for precise filtering.

Querying Documents

Learn how to retrieve documents from MongoDB collections using find() and findOne(), filters, projections, and cursor methods.

Replica Sets Explained

How MongoDB replica sets provide high availability through automatic failover, elections, and data redundancy across primary and secondary nodes.

Schema Design in MongoDB

Learn how to design MongoDB document schemas around your application's access patterns rather than around abstract normalized tables.

Sharding in MongoDB

How MongoDB distributes data across multiple shards using shard keys, chunks, and a query router to scale horizontally beyond a single server's capacity.

Text and Geospatial Indexes

Learn how MongoDB's text indexes power keyword search and how 2dsphere geospatial indexes enable location-based queries.

The Aggregation Pipeline

Learn how MongoDB's aggregation pipeline transforms documents through an ordered sequence of stages to filter, reshape, and summarize data.

MongoDB Cheat Sheet

MongoDB CRUD operations, aggregation pipeline, and indexing strategies.

Difference Between SQL and NoSQL Databases

SQL databases are relational, store data in structured tables with a fixed schema, and use SQL for querying; NoSQL databases are non-relational, store data in…

What is CAP Theorem?

CAP theorem states that a distributed data store can only guarantee two of three properties at once — Consistency, Availability, and Partition tolerance — duri…

What is the Document Database Model?

A document database stores each record as a self-contained, semi-structured document, typically JSON or BSON, where related fields and nested data live togethe…

How Do You Design Document Schemas in MongoDB?

MongoDB document schema design means choosing, for each relationship in your data, whether to embed related data inside a single document or reference it from…

How Does the MongoDB Aggregation Pipeline Work?

The MongoDB aggregation pipeline processes documents through an ordered sequence of stages, each transforming the stream of documents (filtering, reshaping, gr…

How Does MongoDB Sharding Architecture Work?

MongoDB sharding distributes a collection’s documents across multiple shards (each a replica set) using a shard key, coordinated by lightweight mongos routers…