CRUD operations create, read, update, and delete documents.

Create Operations

Create or insert operations add new documents to a collection. If the collection does not currently exist, insert operations will create the collection.

MongoDB provides the following methods to insert documents into a collection:

• db.collection.insertOne()

• db.collection.insertMany()

In MongoDB, insert operations target a single collection. All write operations in MongoDB are atomic on the level of a single document.

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Read Operations

Read operations retrieve documents from a collection; i.e. query a collection for documents. MongoDB provides the following methods to read documents from a collection:

• db.collection.find()

You can specify query filters or criteria that identify the documents to return.

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Update Operations

Update operations modify existing documents in a collection. MongoDB provides the following methods to update documents of a collection:

• db.collection.updateOne()

• db.collection.updateMany()

• db.collection.replaceOne()

In MongoDB, update operations target a single collection. All write operations in MongoDB are atomic on the level of a single document.

You can specify criteria, or filters, that identify the documents to update. These filters use the same syntax as read operations.

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Delete Operations

Delete operations remove documents from a collection. MongoDB provides the following methods to delete documents of a collection:

• db.collection.deleteOne()

• db.collection.deleteMany()

In MongoDB, delete operations target a single collection. All write operations in MongoDB are atomic on the level of a single document.