Databases and Collections in MongoDB

MongoDB stores data records as documents (BSON documents) in collections. A database holds one or more collections.

You can manage databases and collections using the Atlas UI, mongosh, or MongoDB Compass. This page covers Atlas UI procedures. For self-managed deployments, use mongosh or MongoDB Compass.

Select your client:

The MongoDB Shell, mongosh, is a JavaScript and Node.js REPL environment for interacting with MongoDB deployments. To learn more, see mongosh.

MongoDB Compass is a powerful GUI for querying, aggregating, and analyzing your MongoDB data in a visual environment. To learn more, see MongoDB Compass.

Databases

Select your organization and project

If it's not already displayed, select the organization that contains your project from the Organizations menu in the navigation bar.
If it's not already displayed, select your project from the Projects menu in the navigation bar.

Open the Data Explorer

In the sidebar, click Data Explorer under the Database heading.

The Data Explorer displays.

Issue the use <db> statement:

use myDB

Start MongoDB Compass and connect to your cluster.

To learn more, see Connect to MongoDB.

Select Databases.

The Databases tab lists the existing databases for your deployment.

Create a Database

In MongoDB Atlas, go to the Data Explorer page for your project

If it's not already displayed, select the organization that contains your project from the Organizations menu in the navigation bar.
If it's not already displayed, select your project from the Projects menu in the navigation bar.
In the sidebar, click Data Explorer under the Database heading.
The Data Explorer displays.

Open the Create Database dialog box

In the Connections sidebar, select or hover over your cluster and click the icon to open the Create Database dialog box.

Enter the Database Name and the Collection Name

Enter the Database Name and the Collection Name to create the database and its first collection.

If you want to use custom collation on the collection, select the Use Custom Collation checkbox and select the desired collation settings.

Important

Don't include sensitive information in your database and collection names.

For more information on MongoDB database names and collection names, see Naming Restrictions.

Optional. Specify a time series collection

Select whether the collection is a time series collection. If you select to create a time series collection, specify the time field and granularity. You can optionally specify the meta field and the time for old data in the collection to expire.

Click Create Database

Upon successful creation, the database and the collection appears in the Connections sidebar.

MongoDB creates the database when you first store data for it. Switch to a non-existent database and run:

use myNewDB
db.myNewCollection1.insertOne( { x: 1 } )

insertOne() creates both the database myNewDB and the collection myNewCollection1 if they do not already exist. Be sure that both names follow MongoDB Naming Restrictions.

Open the Databases tab.

Click Create database.

Enter the database and collection names.

Click Create Database.

Collections

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

click to enlarge

Create a Collection

If a collection does not exist, MongoDB creates the collection when you first store data for that collection.

In MongoDB Atlas, go to the Data Explorer page for your project

If it's not already displayed, select the organization that contains your project from the Organizations menu in the navigation bar.
If it's not already displayed, select your project from the Projects menu in the navigation bar.
In the sidebar, click Data Explorer under the Database heading.
The Data Explorer displays.

Open the Create Collection dialog box.

Select or hover over the database, and click the icon to open the Create Collection dialog box.

Enter the Collection Name.

In the Create Collection dialog box, enter the name of the collection you want to create.

MongoDB Atlas also provides Additional preferences. You can choose from the following options:

Important

Don't include sensitive information in your collection name.

For more information on MongoDB collection names, see Naming Restrictions.

Optional. Specify a time series collection.

Click Create Collection.

Upon successful creation, the collection appears underneath the database in the Connections sidebar.

db.myNewCollection2.insertOne( { x: 1 } )
db.myNewCollection3.createIndex( { y: 1 } )

Both insertOne() and createIndex() create their respective collection if it does not already exist. Be sure the collection name follows MongoDB Naming Restrictions.

In the left navigation, click the database name.

Click + next to the database name.

Enter a name in Create Collection.

Click Create Collection.

Explicit Creation

Use db.createCollection() to explicitly create a collection with options such as maximum size or validation rules. Without these options, MongoDB automatically creates collections when you first store data.

To modify these collection options, see collMod.

Explicit creation

In the left navigation, click the database name.

Click Create collection.

Enter the collection name and optional preferences.

Click Create Collection.

MongoDB Compass supports the following additional preferences:

Schema Validation

By default, documents in a collection do not share a schema. Fields and data types can vary across documents.

You can enforce schema validation rules during insert and update operations.

For MongoDB Atlas deployments, the Performance Advisor and the MongoDB Atlas UI detect common schema design issues and suggest modifications that follow MongoDB best practices. To learn more, see Schema Suggestions.

Modifying Document Structure

To add, remove, or retype fields in a collection's documents, update the existing documents.

Unique Identifiers

Collections are assigned an immutable UUID that remains consistent across all replica set members and shards.

To retrieve the UUID for a collection, run either the listCollections command or the db.getCollectionInfos() method.

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Documents

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Databases

Select your organization and project

Open the Data Explorer

Start MongoDB Compass and connect to your cluster.

Select Databases.

Create a Database

In MongoDB Atlas, go to the Data Explorer page for your project

Open the Create Database dialog box

Enter the Database Name and the Collection Name

Important

Optional. Specify a time series collection

Click Create Database

Open the Databases tab.

Click Create database.

Enter the database and collection names.

Click Create Database.

Collections

Create a Collection

In MongoDB Atlas, go to the Data Explorer page for your project

Open the Create Collection dialog box.

Enter the Collection Name.

Important

Optional. Specify a time series collection.

Click Create Collection.

In the left navigation, click the database name.

Click + next to the database name.

Enter a name in Create Collection.

Click Create Collection.

Explicit Creation

Explicit creation

In the left navigation, click the database name.

Click Create collection.

Enter the collection name and optional preferences.

Click Create Collection.

Schema Validation

Modifying Document Structure

Unique Identifiers

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