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MongoDB Manual

Introduction to MongoDB

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  • Document Database
  • Key Features

Welcome to the MongoDB 5.0 Manual! MongoDB is a document database designed for ease of development and scaling.

The manual describes key concepts in MongoDB such as:

  • The query API

  • Operational and administrative references

  • Tutorials and procedures

MongoDB offers both local and cloud-hosted deployment options:

  • For locally hosted deployments, MongoDB offers both a Community and an Enterprise version of the database:

    • MongoDB Community is the source available and free to use edition of MongoDB.

    • MongoDB Enterprise is available as part of the MongoDB Enterprise Advanced subscription and includes comprehensive support for your MongoDB deployment. MongoDB Enterprise also adds enterprise-focused features such as LDAP and Kerberos support, on-disk encryption, and auditing.

  • MongoDB Atlas is a hosted MongoDB Enterprise service option in the cloud which requires no installation overhead and offers a free tier to get started.

You can create a MongoDB database in the following environments:

  • MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

  • MongoDB Enterprise: The subscription-based, self-managed version of MongoDB

  • MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB

To learn more about creating a MongoDB database with the Atlas UI, see Get Started with Atlas.

Document Database

A record in MongoDB is a document, which is a data structure composed of field and value pairs. MongoDB documents are similar to JSON objects. The values of fields may include other documents, arrays, and arrays of documents.

A MongoDB document.

The advantages of using documents are:

  • Documents correspond to native data types in many programming languages.

  • Embedded documents and arrays reduce need for expensive joins.

  • Dynamic schema supports fluent polymorphism.

Collections/Views/On-Demand Materialized Views

MongoDB stores documents in collections. Collections are analogous to tables in relational databases.

In addition to collections, MongoDB supports:

Key Features

High Performance

MongoDB provides high performance data persistence. In particular,

  • Support for embedded data models reduces I/O activity on database system.

  • Indexes support faster queries and can include keys from embedded documents and arrays.

Query API

The MongoDB Query API supports read and write operations (CRUD) as well as:

Tip

See also:

High Availability

MongoDB's replication facility, called replica set, provides:

  • automatic failover

  • data redundancy.

A replica set is a group of MongoDB servers that maintain the same data set, providing redundancy and increasing data availability.

Horizontal Scalability

MongoDB provides horizontal scalability as part of its core functionality:

  • Sharding distributes data across a cluster of machines.

  • Starting in 3.4, MongoDB supports creating zones of data based on the shard key. In a balanced cluster, MongoDB directs reads and writes covered by a zone only to those shards inside the zone. See the Zones manual page for more information.

Support for Multiple Storage Engines

MongoDB supports multiple storage engines:

In addition, MongoDB provides pluggable storage engine API that allows third parties to develop storage engines for MongoDB.

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