db.collection.findOneAndReplace()¶

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Definition
Behavior

Definition¶

db.collection.findOneAndReplace(filter, replacement, options)¶

New in version 3.2.

Modifies and replaces a single document based on the filter and sort criteria.

The findOneAndReplace() method has the following form:

db.collection.findOneAndReplace(
   <filter>,
   <replacement>,
   {
     projection: <document>,
     sort: <document>,
     maxTimeMS: <number>,
     upsert: <boolean>,
     returnNewDocument: <boolean>
   }
)

The findOneAndReplace() method takes the following parameters:

Parameter	Type	Description
`filter`	document	The selection criteria for the update. The same query selectors as in the `find()` method are available. Specify an empty document `{ }` to replace the first document returned in the collection.
`replacement`	document	The replacement document. Cannot contain update operators. The `<replacement>` document cannot specify an `_id` value that differs from the replaced document.
`projection`	document	Optional. A subset of fields to return. To return all fields in the matching document, omit this parameter.
`sort`	document	Optional. Specifies a sorting order for the documents matched by the `filter`. See `cursor.sort()`.
`maxTimeMS`	number	Optional. Specifies a time limit in milliseconds within which the operation must complete. Throws an error if the limit is exceeded.
`upsert`	boolean	Optional. When `true`, `findOneAndReplace()` either: Inserts the document from the `replacement` parameter if no document matches the `filter`. Returns `null` after inserting the new document, unless `returnNewDocument` is `true`. Replaces the document that matches the `filter` with the `replacement` document. MongoDB will add the `_id` field to the replacement document if it is not specified in either the `filter` or `replacement` documents. If `_id` is present in both, the values must be equal. To avoid multiple upserts, ensure that the `query` fields are uniquely indexed. Defaults to `false`.
`returnNewDocument`	boolean	Optional. When `true`, returns the replacement document instead of the original document. Defaults to `false`.

Returns:	Returns either the original document or, if `returnNewDocument: true`, the replacement document.

Behavior¶

findOneAndReplace() replaces the first matching document in the collection that matches the filter. The sort parameter can be used to influence which document is modified.

The projection parameter takes a document in the following form:

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{ field1 : < boolean >, field2 : < boolean> ... }

The <boolean> value can be any of the following:

1 or true to include the field. The method returns the _id field even if it is not explicitly stated in the projection parameter.
0 or false to exclude the field. This can be used on any field, including _id.

Examples¶

Replace A Document¶

The scores collection contains documents similar to the following:

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{ "_id" : 1521, "team" : "Fearful Mallards", "score" : 25000 },
{ "_id" : 2231, "team" : "Tactful Mooses", "score" : 23500 },
{ "_id" : 4511, "team" : "Aquatic Ponies", "score" : 19250 },
{ "_id" : 5331, "team" : "Cuddly Zebras", "score" : 15235 },
{ "_id" : 3412, "team" : "Garrulous Bears", "score" : 22300 }

The following operation finds a document with score less than 20000 and replaces it:

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db.scores.findOneAndReplace(
   { "score" : { $lt : 20000 } },
   { "team" : "Observant Badgers", "score" : 20000 }
)

The operation returns the original document that has been replaced:

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{ "_id" : 2512, "team" : "Aquatic Ponies", "score" : 19250 }

If returnNewDocument was true, the operation would return the replacement document instead.

Although multiple documents meet the filter criteria, db.collection.findOneAndReplace replaces only one document.

Sort and Replace A Document¶

The scores collection contains documents similar to the following:

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{ "_id" : 1521, "team" : "Fearful Mallards", "score" : 25000 },
{ "_id" : 2231, "team" : "Tactful Mooses", "score" : 23500 },
{ "_id" : 4511, "team" : "Aquatic Ponies", "score" : 19250 },
{ "_id" : 5331, "team" : "Cuddly Zebras", "score" : 15235 },
{ "_id" : 3412, "team" : "Garrulous Bears", "score" : 22300 }

By including ascending sort order on the score field, the following example replaces the document with lowest score among the matching documents:

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db.scores.findOneAndReplace(
   { "score" : { $lt : 20000 } },
   { "team" : "Observant Badgers", "score" : 20000 },
   { sort: { "score" : 1 } }
)

The operation returns the original document that has been replaced:

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{ "_id" : 5112, "team" : "Cuddly Zebras", "score" : 15235 }

See Replace A Document for the non-sorted result of this command.

Project Specific Fields in Return Document¶

The scores collection contains documents similar to the following:

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{ "_id" : 1521, "team" : "Fearful Mallards", "score" : 25000 },
{ "_id" : 2231, "team" : "Tactful Mooses", "score" : 23500 },
{ "_id" : 4511, "team" : "Aquatic Ponies", "score" : 19250 },
{ "_id" : 5331, "team" : "Cuddly Zebras", "score" : 15235 },
{ "_id" : 3412, "team" : "Garrulous Bears", "score" : 22300 }

The following operation uses projection to only display the team field in the returned document:

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db.scores.findOneAndReplace(
   { "score" : { $lt : 22250 } },
   { "team" : "Therapeutic Hamsters", "score" : 22250 },
   { sort : { "score" : 1 }, projection: { "_id" : 0, "team" : 1 } }
)

The operation returns the original document with only the team field:

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{ "team" : "Cuddly Zebras" }

Replace Document with Time Limit¶

The following operation sets a 5ms time limit to complete:

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try {
   db.scores.findOneAndReplace(
      { "score" : { $gt : 25000 } },
      { "team" : "Emphatic Rhinos", "score" : 25010 },
      { maxTimeMS: 5 }
   );
} catch(e){
   print(e);
}

If the operation exceeds the time limit, it returns:

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Error: findAndModifyFailed failed: { "ok" : 0, "errmsg" : "operation exceeded time limit", "code" : 50 }

Replace Document with Upsert¶

The following operation uses the upsert field to insert the replacement document if nothing matches the filter:

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try {
   db.scores.findOneAndReplace(
      { "team" : "Fortified Lobsters" },
      { "_id" : 6019, "team" : "Fortified Lobsters" , "score" : 32000},
      { upsert : true, returnNewDocument: true }
   );
} catch (e){
   print(e);
}

The operation returns the following:

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{
   "_id" : 6019,
   "team" : "Fortified Lobsters",
   "score" : 32000
}

If returnNewDocument was false, the operation would return null as there is no original document to return.

← db.collection.findOneAndDelete() db.collection.findOneAndUpdate() →