db.collection. findAndModify ( document )

Modifies and returns a single document. By default, the returned document does not include the modifications made on the update. To return the document with the modifications made on the update, use the new option. The findAndModify() method is a shell helper around the findAndModify command.

The findAndModify() method has the following form:

Changed in version 3.6.

    query: <document>,
    sort: <document>,
    remove: <boolean>,
    update: <document>,
    new: <boolean>,
    fields: <document>,
    upsert: <boolean>,
    bypassDocumentValidation: <boolean>,
    writeConcern: <document>,
    collation: <document>,
    arrayFilters: [ <filterdocument1>, ... ]

The db.collection.findAndModify() method takes a document parameter with the following embedded document fields:

Parameter Type Description
query document

Optional. The selection criteria for the modification. The query field employs the same query selectors as used in the db.collection.find() method. Although the query may match multiple documents, findAndModify() will only select one document to modify.

If unspecified, defaults to an empty document.

Starting in MongoDB 3.6.14+ (and 3.4.23+), the operation errors if the query argument is not a document.

sort document

Optional. Determines which document the operation modifies if the query selects multiple documents. findAndModify() modifies the first document in the sort order specified by this argument.

Starting in MongoDB 3.6.14+ (and 3.4.23+), the operation errors if the sort argument is not a document.

remove boolean Must specify either the remove or the update field. Removes the document specified in the query field. Set this to true to remove the selected document . The default is false.
update document Must specify either the remove or the update field. Performs an update of the selected document. The update field employs the same update operators or field: value specifications to modify the selected document.
new boolean Optional. When true, returns the modified document rather than the original. The findAndModify() method ignores the new option for remove operations. The default is false.
fields document

Optional. A subset of fields to return. The fields document specifies an inclusion of a field with 1, as in: fields: { <field1>: 1, <field2>: 1, ... }. See projection.

Starting in MongoDB 3.6.14+ (and 3.4.23+), the operation errors if the fields argument is not a document.

upsert boolean

Optional. Used in conjuction with the update field.

When true, findAndModify() either:

  • Creates a new document if no documents match the query. For more details see upsert behavior.
  • Updates a single document that matches the query.

To avoid multiple upserts, ensure that the query fields are uniquely indexed.

Defaults to false.

bypassDocumentValidation boolean

Optional. Enables db.collection.findAndModify to bypass document validation during the operation. This lets you update documents that do not meet the validation requirements.

New in version 3.2.

writeConcern document

Optional. A document expressing the write concern. Omit to use the default write concern.

New in version 3.2.

maxTimeMS integer Optional. Specifies a time limit in milliseconds for processing the operation.
collation document


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.

arrayFilters array

Optional. An array of filter documents that determines which array elements to modify for an update operation on an array field.

In the update document, use the $[<identifier>] filtered positional operator to define an identifier, which you then reference in the array filter documents. You cannot have an array filter document for an identifier if the identifier is not included in the update document.


The <identifier> must begin with a lowercase letter and contain only alphanumeric characters.

You can include the same identifier multiple times in the update document; however, for each distinct identifier ($[identifier]) in the update document, you must specify exactly one corresponding array filter document. That is, you cannot specify multiple array filter documents for the same identifier. For example, if the update statement includes the identifier x (possibly multiple times), you cannot specify the following for arrayFilters that includes 2 separate filter documents for x:

  { "x.a": { $gt: 85 } },
  { "x.b": { $gt: 80 } }

However, you can specify compound conditions on the same identifier in a single filter document, such as in the following examples:

  { $or: [{"x.a": {$gt: 85}}, {"x.b": {$gt: 80}}] }

  { $and: [{"x.a": {$gt: 85}}, {"x.b": {$gt: 80}}] }

  { "x.a": { $gt: 85 }, "x.b": { $gt: 80 } }

For examples, see Specify arrayFilters for an Array Update Operations.

New in version 3.6.

Return Data

For remove operations, if the query matches a document, findAndModify() returns the removed document. If the query does not match a document to remove, findAndModify() returns null.

For update operations, findAndModify() returns one of the following:

  • If the new parameter is not set or is false:
    • the pre-modification document if the query matches a document;
    • otherwise, null.
  • If new is true:
    • the modified document if the query returns a match;
    • the inserted document if upsert: true and no document matches the query;
    • otherwise, null.

Changed in version 3.0: In previous versions, if for the update, sort is specified, and upsert: true, and the new option is not set or new: false, db.collection.findAndModify() returns an empty document {} instead of null.


Upsert and Unique Index

When findAndModify() includes the upsert: true option and the query field(s) is not uniquely indexed, the method could insert a document multiple times in certain circumstances.

In the following example, no document with the name Andy exists, and multiple clients issue the following command:

    query: { name: "Andy" },
    sort: { rating: 1 },
    update: { $inc: { score: 1 } },
    upsert: true

Then, if these clients’ findAndModify() methods finish the query phase before any command starts the modify phase, and there is no unique index on the name field, the commands may all perform an upsert, creating multiple duplicate documents.

To prevent the creation of multiple duplicate documents with the same name, create a unique index on the name field. With this unique index in place, the multiple methods will exhibit one of the following behaviors:

  • Exactly one findAndModify() successfully inserts a new document.
  • Zero or more findAndModify() methods update the newly inserted document.
  • Zero or more findAndModify() methods fail when they attempt to insert documents with the same name. If the method fails due to the unique index constraint violation on the name field, you can retry the method. Absent a delete of the document, the retry should not fail.

Sharded Collections

When using findAndModify in a sharded environment, the query must contain the shard key for all operations against the sharded cluster for the sharded collections.

findAndModify operations issued against mongos instances for non-sharded collections function normally.

Document Validation

The db.collection.findAndModify() method adds support for the bypassDocumentValidation option, which lets you bypass document validation when inserting or updating documents in a collection with validation rules.

Comparisons with the update Method

When updating a document, findAndModify() and the update() method operate differently:

  • By default, both operations modify a single document. However, the update() method with its multi option can modify more than one document.

  • If multiple documents match the update criteria, for