What Is MongoDB and How It Operates? A Full Guide

What is mongodb complete guide for beginners

Are you an aspiring professional looking to launch a career in NoSQL databases and MongoDB? Look no further. This comprehensive guide is specifically designed for database administrators, software developers, IT professionals, and others seeking to understand MongoDB and its applications. We will cover the core concepts, key features, and the differences between MongoDB and traditional relational databases. By the end of this guide, you’ll have a solid foundation to help you navigate the world of MongoDB with confidence.

What Is MongoDB?

As a NoSQL database system, MongoDB is an open-source solution that provides high performance, high availability, and automatic scaling. It is a document-oriented database that stores data in flexible, JSON-like documents called BSON. This allows for a more expressive and powerful data representation than traditional tabular relational databases. MongoDB gets its name from the word “humongous,” reflecting its ability to handle large amounts of data.

Supporting various programming languages, including Java, JavaScript, Python, C++, C#, and Ruby, among others, it is beneficial for a wide range of professionals, such as database administrators, software developers, architects, and IT developers. Note that the primary language used to interact with MongoDB is JavaScript, with queries written in JSON format.

One critical difference between MongoDB and traditional Relational Database Management Systems (RDBMS) is their approach to data storage. While RDBMS uses tables with a fixed schema, MongoDB stores data in flexible, schema-less documents. This allows for a more adaptable and dynamic data model, which is especially useful when working with large-scale, diverse datasets.

Hence, when answering a question like “What is MongoDB?”, one should also state that it’s a powerful, flexible, and scalable NoSQL database system that supports various programming languages and caters to a wide range of professionals. Its document-oriented approach offers a distinct advantage over traditional relational databases when dealing with complex, varied data.

Guide to what is MongoDB

How Does MongoDB Work?

MongoDB operates differently from traditional relational databases, with its architecture centered around the concept of collections and documents.

What is a collection in MongoDB?

A collection is similar to a table in an RDBMS. However, it does not enforce a fixed schema. Instead, MongoDB collections consist of documents with varying fields and structures. Documents in MongoDB are stored in a binary JSON format called BSON, which allows for efficient storage and retrieval of complex data types like arrays and nested documents. These documents can be easily updated, making MongoDB particularly suitable for handling large-scale, dynamic data.

When a client connects to a MongoDB server, it communicates with the server using a query language based on JSON. The server processes the queries, performs the requested operations, and returns the results in BSON format.

MongoDB uses a distributed architecture for high availability and horizontal scaling. Employing a technique called sharding to distribute data across multiple servers effectively balances the load and increases the system’s overall capacity. MongoDB uses replica sets to ensure high availability, which consist of multiple copies of the data stored on different servers. These replicas maintain a consistent state through an automated replication process. In case the primary server fails, one of the secondary replicas takes over as the new primary, ensuring minimal downtime and data loss.

In essence, MongoDB’s flexible, document-based architecture, distributed design, and robust query language enable it to handle diverse and large-scale datasets efficiently. Its high availability and automatic scaling capabilities make it a popular choice for modern application development.

What Is The Difference Between MongoDB & RDBMS?

These are two distinct types of database systems, each with its own set of advantages and limitations. The key differences between MongoDB and RDBMS (Relational Database Management System) are as follows:

  1. Data Model: MongoDB uses a flexible, schema-less document model, while RDBMS follows a structured table-based model with a fixed schema. This flexibility in MongoDB allows for easier adaptation to changing requirements and handling complex, hierarchical data.
  2. Query Language: MongoDB uses a JSON-based query language that can handle complex queries and aggregations, whereas RDBMS relies on SQL, a widely-used and standardized language for querying and managing relational databases.
  3. Scalability: MongoDB is designed for horizontal scaling, using sharding to distribute data across multiple servers. RDBMS, on the other hand, typically scales vertically, which can become expensive and challenging as the database grows.
  4. Data Consistency: RDBMS enforces ACID (Atomicity, Consistency, Isolation, Durability) properties, ensuring data consistency and reliability. MongoDB, however, follows the BASE (Basically Available, Soft state, Eventual consistency) model, prioritizing availability and performance over strict consistency.

MongoDB is a better fit for applications that require flexible data models, high availability, and horizontal scaling. At the same time, RDBMS is more suitable for applications with strict data consistency requirements and well-defined schema structures.

Why Is MongoDB Used?

Programmer smiling suggesting to learn coding

MongoDB is widely used for several reasons:

  • Flexibility: Its schema-less data model allows developers to easily adapt to changing requirements and manage unstructured data.
  • Scalability: Designed for horizontal scaling, MongoDB can handle large data sets and high traffic loads with ease, making it suitable for big data applications.
  • Performance: MongoDB’s indexing and caching capabilities ensure high performance, even with complex queries, providing fast read and write operations.
  • High availability: Replication and automatic failover features ensure data availability and resilience, minimizing downtime and data loss.
  • Rich query language: MongoDB’s JSON-based query language supports complex queries, aggregations, and geospatial operations, allowing developers to work with diverse data types.
  • Developer-friendly: With support for multiple programming languages and platforms, MongoDB is accessible to many developers, making it a popular choice in the software development community.

Key Components of MongoDB Architecture

MongoDB’s architecture is designed to provide a scalable, flexible, and high-performing database system. The seven key components that make up this architecture are:

  1. Document: MongoDB stores data in a flexible, JSON-like format called BSON, which allows for rich data structures, such as arrays and nested documents.
  2. Collection: A group of MongoDB documents, similar to a table in a relational database, but without a fixed schema.
  3. Database: A container for collections, each MongoDB instance can host multiple databases, each with its unique set of data files.
  4. Query Optimizer: MongoDB uses a query optimizer to analyze queries and determine the most efficient way to access the requested data.
  5. Indexing: MongoDB allows for the creation of indexes on fields within documents, helping improve query performance by enabling faster lookups.
  6. Replication: By replicating data across multiple servers, MongoDB ensures high availability, fault tolerance, and disaster recovery.
  7. Sharding: To support horizontal scaling, MongoDB offers sharding, which distributes data across multiple servers, allowing the system to handle large amounts of data and high query loads.

MongoDB Features

MongoDB offers a range of powerful features that make it an attractive choice for many organizations and developers. Some of the key features include:

  • Document-oriented: MongoDB is a document-oriented database, which means it stores data in a semi-structured format, allowing for greater flexibility and scalability.
  • Schema-less: It’s schema-less, meaning it does not require a fixed structure for the data. This makes it easier to adapt to changing requirements and store complex data.
  • High performance: Designed to deliver high performance for both read and write operations, MongoDB is suitable for high-traffic applications.
  • Horizontal scalability: MongoDB supports horizontal scaling through sharding, which allows you to distribute your data across multiple servers, ensuring optimal performance and resilience.
  • High availability: It provides built-in replication and automatic failover, ensuring high availability of your data and minimizing downtime.
  • Rich query language: MongoDB also offers a rich query language that supports a wide range of query types, including complex aggregations and geospatial queries.
  • Support for multiple storage engines: Last but not least, MongoDB supports multiple storage engines, allowing you to choose the best option for your specific use case and performance requirements.

Thus, through the journey of discovering what is MongoDB, these features prove that it’s a powerful and versatile database solution capable of handling a wide range of use cases and requirements. Its flexibility and scalability make it an ideal choice for organizations looking to build modern, data-driven applications.

Common Use Cases

MongoDB is a versatile database system used in various scenarios and industries. Some of the common use cases include but are not limited to:

Content Management Systems (CMS)

MongoDB’s flexible schema and ability to store complex data make it an excellent choice for building content management systems that can handle a variety of content types, such as text, images, and videos.

IoT and Sensor Data

Its high performance and horizontal scaling capabilities make it well-suited for storing and analyzing the massive amounts of data generated by IoT devices and sensors.


MongoDB has a rich query language and flexible data model, allowing easy product catalogs, inventory, and customer data management. This makes it an ideal choice for e-commerce applications.


Its high performance and ability to handle a large number of concurrent users make it a popular choice for building online gaming platforms that need to store and manage player data, game state, and other real-time information.

Real-Time Analytics

MongoDB’s high performance and built-in support for complex aggregations make it suitable for real-time analytics applications that require the processing and analysis of large volumes of data quickly.

Mobile Applications

The ability to scale horizontally and provide high availability makes it an attractive option for building mobile applications that need to handle a large number of users and provide a seamless experience across different devices.

Personalization and Recommendation

MongoDB’s flexibility and rich query language make it a great choice for building personalized experiences and recommendation engines that can analyze user behavior and preferences to deliver relevant content and suggestions.

MongoDB use cases

Pros and Cons in a Nutshell

MongoDB Advantages

MongoDB offers numerous advantages over traditional relational databases and other NoSQL databases. Here are a few things to keep in mind:

  • Flexible data model: MongoDB allows for a schema-less data model, providing flexibility in storing and managing diverse data types. This enables developers to easily adapt the data model as application requirements change over time without the need for costly schema migrations.
  • Horizontal scalability: One of its core strengths is its ability to scale horizontally by sharding data across multiple servers. This allows for easy handling of growing data sets and increased user traffic without impacting performance.
  • Rich query language: MongoDB offers a powerful language supporting complex queries and aggregations. This allows developers to easily manipulate and analyze data within the database, reducing the need for external processing.
  • Geospatial support: MongoDB includes built-in support for geospatial data types and queries, making it an excellent choice for applications that require location-based data analysis and storage.
  • Easy integration with big data and analytics tools: The flexible data model and support for multiple data formats make it easy to integrate with various big data and analytics tools, such as Hadoop and Spark, enabling organizations to gain insights from their data more efficiently.
  • Strong community and ecosystem: MongoDB has a large and active community, providing a wealth of resources, support, and third-party tools to help developers get the most out of the database. Additionally, MongoDB, Inc. offers commercial support and services to help organizations ensure the success of their projects.
  • Open-source: As an open-source, there is continuous improvement through community contributions enabling organizations to customize the database to meet their specific needs.

These advantages make MongoDB an attractive choice for those looking to develop modern, scalable, and high-performance applications while benefiting from the database’s flexibility, performance, and ease of use.

MongoDB Disadvantages

While MongoDB offers many advantages, it also has some limitations and drawbacks worth considering:

  • Lack of support for transactions: Multi-document transactions were introduced in MongoDB 4.0, but they have limitations compared to traditional relational databases.
  • Limited support for joins: MongoDB doesn’t support standard SQL-style joins, which can make working with related data across multiple collections challenging.
  • Higher storage and memory usage: MongoDB’s flexible data model can consume more storage space, and its caching and indexing may lead to increased resource usage.
  • Complexity in managing sharded clusters: Managing and maintaining sharded clusters can be complex, especially in large-scale deployments, requiring additional expertise and resources.
  • Less mature ecosystem: MongoDB’s ecosystem may not be as mature or extensive as those of more established relational databases, potentially leading to fewer experienced developers, tools, and support for some use cases.

How to Deploy and Set Up MongoDB?

As a rule, the process involved a few steps. Here are the most crucial ones:

Step 1. Download

Get the appropriate MongoDB package for your operating system from the official MongoDB website.

Step 2. Installation

Follow the installation instructions specific to your platform (Windows, macOS, or Linux) to install MongoDB on your system.

Pro hint: You can also check WildLearner’s simple course and learn how to install MongoDB in minutes. The course will explain the initial installation and also provide some practical insights for further steps.

Step 3. Configuration

Configure MongoDB settings by editing the configuration file (typically named “mongod.conf”). Set parameters such as storage paths, security options, and networking settings according to your requirements. Refer to the MongoDB Configuration documentation for more information.

Step 4. Starting the MongoDB server

Launch the MongoDB server using the “mongod” command, followed by any required command-line options or the path to the configuration file. Learn more about Starting MongoDB.

Step 5. Connecting to the server

Use the “mongo” shell command to connect to the running MongoDB server, allowing you to interact with the database. See the Mongo Shell documentation for details.

Step 6. Creating a database

Once connected, create a new database and collections as needed for your application. Find out how to Create Database and Collections.

Step 7. Importing data

Optionally, import data from JSON, CSV, or TSV files using the “mongoimport” tool. Visit the Mongoimport documentation for guidance.


So, what is MongoDB? In brief, it’s an ideal choice for professionals aspiring to launch a career in NoSQL databases, including database administrators, software developers, and system administrators. With its versatility and powerful features, MongoDB serves a wide range of use cases. 

To deepen your understanding and enhance your skills, consider enrolling in WildLearner’s newly launched certified online course on MongoDB, which will provide you with the knowledge and expertise to excel in this thriving field.