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What is MongoDB?

An introduction to MongoDB and NoSQL databases

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Overview

Let’s explore MongoDB, one of the most popular NoSQL databases, and understand how it differs from traditional relational databases.


What is MongoDB?

MongoDB is a NoSQL database that offers more flexible data storage and management compared to traditional relational databases.

The name “MongoDB” comes from “humongous,” reflecting its design for handling large-scale data.

Key Characteristics
  • Document-oriented database
  • Schema-less design
  • Built for scalability
  • High performance


Understanding NoSQL

NoSQL (“Not Only SQL”) was developed as an alternative to traditional RDBMS, addressing their limitations. NoSQL databases typically offer:

Main Types of NoSQL Databases
  1. Document-Oriented Database
    • Examples: MongoDB, CouchDB
    • Stores JSON/XML-like documents
  2. Key-Value Store
    • Examples: Redis, DynamoDB
    • Simple key-value pair storage
  3. Wide Column Store
    • Examples: Cassandra, HBase
    • Uses column families for data organization
  4. Graph Database
    • Examples: Neo4j, Amazon Neptune
    • Optimized for relationship data


Key Features of MongoDB

Document Database

MongoDB stores data in flexible, JSON-like documents where each document can have different fields.

Schema-less Design

Collections can contain documents with varying structures, ideal for evolving data requirements.

Horizontal Scalability

Supports sharding for distributing data across multiple servers.

Query Capabilities

// Example of MongoDB query
db.collection.find({
  age: { $gt: 25 },
  status: "active"
}).sort({ name: 1 })

High Availability

Uses replica sets for automatic failover and data redundancy.


Understanding Sharding

MongoDB vs RDBMS Sharding
  • Mechanism
    • MongoDB: Automated sharding process
    • RDBMS: Manual configuration required
  • Data Model Flexibility
    • MongoDB: Flexible schema across shards
    • RDBMS: Fixed schema constraints
  • Cross-Shard Transactions
    • MongoDB: Native support since version 4.2
    • RDBMS: Can be complex to implement


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