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Description

MongoDB Error 48, 'Namespace Exists', occurs when an operation attempts to create a collection, index, or view with a name that is already in use within the current database. This typically happens during database schema initialization or when re-running creation scripts.

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Error Message

Namespace Exists

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Known Causes

3 known causes

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Collection Name Conflict

You tried to create a new collection using `db.createCollection()` or implicitly via an insert operation, but a collection with the same name already exists in the database.

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Duplicate Index Creation

An attempt was made to create an index on a collection using `db.collection.createIndex()`, but an index with the exact same specification already exists for that collection.

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View Name Collision

An operation to create a new view using `db.createView()` failed because a view or collection with the specified name already occupies that namespace.

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Solutions

4 solutions available

1. Drop and Recreate Collection easy

Remove existing collection first

1

Drop existing collection

db.existingCollection.drop()

2

Create new collection

db.createCollection("existingCollection", {
  validator: { $jsonSchema: { ... } }
})

2. Use Different Name easy

Choose unique collection name

1

Check existing collections

show collections

2

Use unique name

db.createCollection("users_v2")

3. Rename Existing Collection easy

Move existing collection out of the way

1

Rename existing collection

db.existingCollection.renameCollection("existingCollection_backup")

2

Create new collection with original name

db.createCollection("existingCollection")

4. Check for View with Same Name easy

Views and collections share namespace

1

List views

db.getCollectionInfos({ type: "view" })

2

Drop view if exists

db.existingView.drop()

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Related Errors

5 related errors

MongoDB Error 48: Collection or Index Exists