Collections
A collection is a grouping of MongoDB documents. Documents within a collection can have different fields. A collection is the equivalent of a table in a relational database system. A collection exists within a single database
Collections Screen
The Collections screen lists the existing collections and views in the selected database. Each list item includes the name and other general information for the collection or view.
To access the Collections screen for a database, from the Databases screen either:
- Click a Database Name in the main Databases view, or
- Click a database in the left navigation.
Collection Information
The Collections screen displays the following information for each collection in the selected database:
- Collection name
Number of documents in the collection
NoteCompass bases the document count that appears on the Collections screen on cached metadata using collStats. This count might differ from the actual document count in the collection. For example, an unexpected shutdown can throw off the count. Use the db.collection.countDocuments() method for the most accurate document count.
- Average size of documents in the collection
- Total size of all documents in the collection
- Number of indexes on the collection
- Total size of all indexes on the collection
- Collation properties for the collection. Hover over a Collation banner to view the properties for that collection.
Create a Collection
You can create new collections in an existing database.
Click the Create Collection button.
From the Collections screen, click the Create Collection button.
Enter the collection information.
In the Create Collection dialog, enter the name of the collection to create.
If you want to create a capped collection, select the Capped Collection checkbox and enter the maximum bytes.
If you want to use custom collation on the collection, select the Use Custom Collation checkbox and select the desired collation settings.
Click Create Collection to create the collection.
Drop a Collection
Click the trash can icon to delete a collection.
From the Collections screen, click on the trash can for the collection to delete. A confirmation dialog appears.
Confirm the collection to delete.
In the dialog, enter the name of the collection to delete.
Click Drop Collection to drop the collection.
Collection Details
The Collection Detail screen shows detailed information for a collection, including the documents the collection contains. To see collection details, either:
- Click a Collection Name in the main Collections screen, or
- Click a collection in the left navigation.
- Open the collection in a new tab.
After you select a collection, Compass shows you that collection's Documents tab. Compass provides the following collection information and functionality in the detailed view:
- Manage Documents
- Import and Export Data to / from the collection
- Aggregation Pipeline Builder
- Schema Analysis
- View Query Performance
- Manage Indexes
- Set Validation Rules for Your Schema
The following functionality is not available if you are connected to a Data Lake:
- Import data into a collection
- Schema Analysis
- View Query Performance
- Manage Indexes
- Set Validation Rules for Your Schema
Tabbed View
You can open multiple Collection Detail screens in separate tabs. To open a new tab to view collection details:
Click the caret icon next to the database which contains the collection you wish to view.
Hover over the desired collection.
Click the appearing ellipses (...) button.
Click Open in New Tab.
Limitations
- Creating and dropping collections is not permitted in MongoDB Compass Readonly Edition.
- The Create Collection button is not available if you are connected to a Data Lake.