Delete operation

The delete operation removes a document from the database when a given query is met. Two methods for deleting documents in a collection include deleteOne() and deleteMany().

Delete a single document

The deleteOne() method removes a single document (the first document that matches the query parameter) completely from the collection.

db.collection.deleteOne({<query_params>})

Insert the following list of documents:

db.scientists.insertMany([
  {
    firstname: 'Thomas',
    lastname: 'Edison',
    born: 1847,
    invention: 'LightBulb',
    nobel: true
  },
  {
    firstname: 'Graham',
    lastname: 'Bell',
    born: 1847,
    invention: 'telephone',
    nobel: false
  },
  {
    firstname: 'Nikola',
    lastname: 'Tesla',
    born: 1856,
    invention: 'Tesla coil',
    nobel: false
  },
  {
    firstname: 'Ada',
    lastname: 'Lovelace',
    born: 1815,
    invention: 'Computer programming',
    nobel: false
  }
])

This operation returns a response showing acknowledged as true and the ObjectId of the four inserted documents:

{
  acknowledged: true,
  insertedIds: {
    '0': ObjectId("63470121d7a4a1b0b38eb2df"),
    '1': ObjectId("63470121d7a4a1b0b38eb2e0"),
    '2': ObjectId("63470121d7a4a1b0b38eb2e1"),
    '3': ObjectId("63470121d7a4a1b0b38eb2e2")
  }
}

Next, delete a document from the collection where the field nobel is set to false.

db.scientists.deleteOne({ nobel: false })

This operation returns a response that shows that a single document was deleted from the collection.

{ acknowledged: true, deletedCount: 1 }

Deletes multiple documents

To delete multiple documents at once, use the deleteMany() method. Using the same record from earlier, let’s delete all the documents with nobel set to false.

db.scientists.deleteMany({ nobel: false })

This command removes all the documents in the collection that matches the query.