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A collection is nothing but a folder that contains all the documents. When using capped collections, there is a cap on the number of records you can add to the collection.

The maximum size of a document is 16MB. Sometimes you want to build a new collection and delete documents from the current collection.

You can choose one of the two options to truncate the collection below according to your requirement. In today’s article, we will learn how to truncate a collection in MongoDB.

Truncating a collection in MongoDB

drop()We can use either or as per our project requirement remove(). If we want to remove all data and indexes of a collection, we can use drop()while remove()to remove the matching documents and keep (update) the indexes.

Let's start with the drop() method below.

Using the drop() method

In MongoDB, you can drop()remove a collection from a database using the remove method. A collection is deleted from the database, and any indexes linked to the dumped collection are also deleted.

db.collection.drop()The method throws an error when used with arguments and does not accept any arguments. It returns true if the drop command successfully deleted a collection.

It returns false when there is no collection to drop. You can find more information about the drop() method here.

syntax:

> db.collectionName.drop()

Let's use the following example to understand the above ideas:

> db.users.drop()

We are deleting all user collections from the previous example, which will automatically delete any associated indexes as well. Run the above line of code in a MongoShell that is compatible with MongoDB.

It will display the following results:

true

Using the remove() method

In MongoDB, you can remove()remove a collection from the database using the method.

However, this approach will be considerably slower in a replica set scenario, as the oplog will contain an entry for each deleted document, rather than a single collection delete command.

remove()Method is incompatible with capped aggregates. remove()Method is not applicable to 'aggregates' of time series. Select a valid method based on your needs.

If remove()a collection is successfully deleted, it returns a WriteResult object containing the status of the operation.

syntax:

> db.collectionName.remove({})

Let's use the following example to understand the above ideas:

> db.users.remove({})

In the above example, the complete user collection data is deleted, but this method does not delete the index linked to the collection. Run the above line of code in a MongoShell compatible with MongoDB. It will display the following result:

WriteResult({ "nRemoved" : 3300 })