db.collection.remove()¶

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Definition¶

db.collection.remove()¶

Removes documents from a collection.

The db.collection.remove() method can have one of two syntaxes. The remove() method can take a query document and an optional justOne boolean:

db.collection.remove(
   <query>,
   <justOne>
)

Or the method can take a query document and an optional remove options document:

New in version 2.6.

db.collection.remove(
   <query>,
   {
     justOne: <boolean>,
     writeConcern: <document>,
     collation: <document>
   }
)

Parameter	Type	Description
`query`	document	Specifies deletion criteria using query operators. To delete all documents in a collection, pass an empty document (`{}`). Changed in version 2.6: In previous versions, the method invoked with no query parameter deleted all documents in a collection.
`justOne`	boolean	Optional. To limit the deletion to just one document, set to `true`. Omit to use the default value of `false` and delete all documents matching the deletion criteria.
`writeConcern`	document	Optional. A document expressing the write concern. Omit to use the default write concern. See Write Concern. New in version 2.6.
`collation`	document	Optional. Specifies the collation to use for the operation. Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks. The collation option has the following syntax: collation: { locale: <string>, caseLevel: <boolean>, caseFirst: <string>, strength: <int>, numericOrdering: <boolean>, alternate: <string>, maxVariable: <string>, backwards: <boolean> } When specifying collation, the `locale` field is mandatory; all other collation fields are optional. For descriptions of the fields, see Collation Document. If the collation is unspecified but the collection has a default collation (see `db.createCollection()`), the operation uses the collation specified for the collection. If no collation is specified for the collection or for the operations, MongoDB uses the simple binary comparison used in prior versions for string comparisons. You cannot specify multiple collations for an operation. For example, you cannot specify different collations per field, or if performing a find with a sort, you cannot use one collation for the find and another for the sort. New in version 3.4.

Changed in version 2.6: The remove() returns an object that contains the status of the operation.

Returns:	A WriteResult object that contains the status of the operation.

Behavior¶

Write Concern¶

Changed in version 2.6.

The remove() method uses the delete command, which uses the default write concern. To specify a different write concern, include the write concern in the options parameter.

Query Considerations¶

By default, remove() removes all documents that match the query expression. Specify the justOne option to limit the operation to removing a single document. To delete a single document sorted by a specified order, use the findAndModify() method.

When removing multiple documents, the remove operation may interleave with other read and/or write operations to the collection. For unsharded collections, you can override this behavior with the $isolated operator, which “isolates” the remove operation and disallows yielding during the operation. This ensures that no client can see the affected documents until they are all processed or an error stops the remove operation.

See Isolate Remove Operations for an example.

Capped Collections¶

You cannot use the remove() method with a capped collection.

Sharded Collections¶

All remove() operations for a sharded collection must include the shard key or the _id field in the query specification. remove() operations without the shard key or the _id field return an error.

Examples¶

The following are examples of the remove() method.

Remove All Documents from a Collection¶

To remove all documents in a collection, call the remove method with an empty query document {}. The following operation deletes all documents from the bios collection:

db.bios.remove( { } )

This operation is not equivalent to the drop() method.

To remove all documents from a collection, it may be more efficient to use the drop() method to drop the entire collection, including the indexes, and then recreate the collection and rebuild the indexes.

Remove All Documents that Match a Condition¶

To remove the documents that match a deletion criteria, call the remove() method with the <query> parameter:

The following operation removes all the documents from the collection products where qty is greater than 20:

db.products.remove( { qty: { $gt: 20 } } )

Override Default Write Concern¶

The following operation to a replica set removes all the documents from the collection products where qty is greater than 20 and specifies a write concern of "w: majority" with a wtimeout of 5000 milliseconds such that the method returns after the write propagates to a majority of the voting replica set members or the method times out after 5 seconds.

Changed in version 3.0: In previous versions, majority referred to the majority of all members of the replica set instead of the majority of the voting members.

db.products.remove(
    { qty: { $gt: 20 } },
    { writeConcern: { w: "majority", wtimeout: 5000 } }
)

Remove a Single Document that Matches a Condition¶

To remove the first document that match a deletion criteria, call the remove method with the query criteria and the justOne parameter set to true or 1.

The following operation removes the first document from the collection products where qty is greater than 20:

db.products.remove( { qty: { $gt: 20 } }, true )

Isolate Remove Operations¶

To isolate the query, include $isolated: 1 in the <query> parameter as in the following examples:

db.products.remove( { qty: { $gt: 20 }, $isolated: 1 } )

Specify Collation¶

New in version 3.4.

Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.

A collection myColl has the following documents:

{ _id: 1, category: "café", status: "A" }
{ _id: 2, category: "cafe", status: "a" }
{ _id: 3, category: "cafE", status: "a" }

The following operation includes the collation option:

db.myColl.remove(
   { category: "cafe", status: "A" },
   { collation: { locale: "fr", strength: 1 } }
)

WriteResult¶

Changed in version 2.6.

Successful Results¶

The remove() returns a WriteResult object that contains the status of the operation. Upon success, the WriteResult object contains information on the number of documents removed:

WriteResult({ "nRemoved" : 4 })

Write Concern Errors¶

If the remove() method encounters write concern errors, the results include the WriteResult.writeConcernError field:

WriteResult({
   "nRemoved" : 21,
   "writeConcernError" : {
      "code" : 64,
      "errInfo" : {
         "wtimeout" : true
      },
      "errmsg" : "waiting for replication timed out"
   }
})

Errors Unrelated to Write Concern¶

If the remove() method encounters a non-write concern error, the results include WriteResult.writeError field:

WriteResult({
   "nRemoved" : 0,
   "writeError" : {
      "code" : 2,
      "errmsg" : "unknown top level operator: $invalidFieldName"
   }
})