> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

# db.collection.findOneAndReplace() (mongosh method)

## Definition

Replaces a single document based on the specified [filter.](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-filter)

## Compatibility

This method is available in deployments hosted in the following environments:

- [MongoDB Atlas](https://www.mongodb.com/docs/atlas): The fully managed service for MongoDB deployments in the cloud

**Note:**

This command is supported in all MongoDB Atlas clusters. For information on Atlas support for all commands, see [Unsupported Commands.](https://www.mongodb.com/docs/atlas/unsupported-commands/)

- [MongoDB Enterprise](https://www.mongodb.com/docs/manual/administration/install-enterprise.md#std-label-install-mdb-enterprise): The subscription-based, self-managed version of MongoDB

- [MongoDB Community](https://www.mongodb.com/docs/manual/administration/install-community.md#std-label-install-mdb-community-edition): The source-available, free-to-use, and self-managed version of MongoDB

## Syntax

The [`findOneAndReplace()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#mongodb-method-db.collection.findOneAndReplace) method has the following form:

```javascript
db.collection.findOneAndReplace(
   <filter>,
   <replacement>,
   {
     writeConcern: <document>,
     projection: <document>,
     sort: <document>,
     maxTimeMS: <number>,
     upsert: <boolean>,
     returnDocument: <string>,
     returnNewDocument: <boolean>,
     collation: <document>
   }
)
```

### Fields and Options

The [`findOneAndReplace()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#mongodb-method-db.collection.findOneAndReplace) method takes the following fields and options:

| Field | Type | Description |
| --- | --- | --- |
| [filter](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-filter) | document | The selection criteria for the update. The same [query selectors](https://www.mongodb.com/docs/manual/reference/mql/query-predicates.md#std-label-query-selectors) as in the [`find()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.find.md#mongodb-method-db.collection.find) method are available. To replace the first document returned in the collection, specify an empty document `{ }`. If unspecified, defaults to an empty document. If the query argument is not a document, the operation returns an error. |
| [replacement](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-replacement) | document | The replacement document. Cannot contain [update operators.](https://www.mongodb.com/docs/manual/reference/mql/update.md#std-label-update-operators-top-level) The `<replacement>` document cannot specify an `_id` value that differs from the replaced document. |
| `writeConcern` | document | Optional. A document expressing the [write concern](https://www.mongodb.com/docs/manual/reference/write-concern.md#std-label-write-concern). Omit to use the default write concern. `{ w: <value>, j: <boolean>, wtimeout: <number> }` Do not explicitly set the write concern for the operation if run in a transaction. To use write concern with transactions, see [Transactions and Write Concern.](https://www.mongodb.com/docs/manual/core/transactions.md#std-label-transactions-write-concern) |
| [projection](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-projection) | document | Optional. A subset of fields to return. To return all fields in the matching document, omit this field. If the projection argument is not a document, the operation errors. |
| [sort](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-sort) | document | Optional. Specifies a sorting order for the documents matched by the [filter.](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-filter) If the sort argument is not a document, the operation errors. See [`cursor.sort()`.](https://www.mongodb.com/docs/manual/reference/method/cursor.sort.md#mongodb-method-cursor.sort) |
| `maxTimeMS` | number | Optional. Specifies a time limit in milliseconds within which the operation must complete. Returns an error if the limit is exceeded. |
| [upsert](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-upsert) | boolean | Optional. When `true`, [`findOneAndReplace()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#mongodb-method-db.collection.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.](https://www.mongodb.com/docs/manual/core/index-unique.md#std-label-index-type-unique) Defaults to `false`. |
| [returnDocument](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-returnDocument) | string | Optional. Starting in [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) 0.13.2, `returnDocument` is an alternative for [returnNewDocument](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-returnNewDocument). If both options are set, `returnDocument` takes precedence. `returnDocument: "before"` returns the original document. `returnDocument: "after"` returns the updated document. |
| [returnNewDocument](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-returnNewDocument) | boolean | Optional. When `true`, returns the replacement document instead of the original document. Defaults to `false`. |
| [collation](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-collation) | document | Optional. Optional. Specifies the [collation](https://www.mongodb.com/docs/manual/reference/collation.md#std-label-collation)  to use for the operation. [Collation](https://www.mongodb.com/docs/manual/reference/collation.md#std-label-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.](https://www.mongodb.com/docs/manual/reference/collation.md#std-label-collation-document-fields) If the collation is unspecified but the collection has a default collation (see [`db.createCollection()`](https://www.mongodb.com/docs/manual/reference/method/db.createcollection.md#mongodb-method-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. |

### Returns

Returns the original document by default. Returns the updated document if [returnDocument](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-returnDocument) is set to `after` or [returnNewDocument](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-returnNewDocument) is set to `true`.

## Behavior

### Document Match

[`db.collection.findOneAndReplace()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#mongodb-method-db.collection.findOneAndReplace) replaces the first matching document in the collection that matches the `filter`. The `sort` field can be used to influence which document is modified.

### Projection

**Important: Language Consistency**

As part of making [`find()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.find.md#mongodb-method-db.collection.find) and [`findAndModify()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findandmodify.md#mongodb-method-db.collection.findAndModify) projection consistent with aggregation's [`$project`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/project.md#mongodb-pipeline-pipe.-project) stage,

- The [`find()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.find.md#mongodb-method-db.collection.find) and [`findAndModify()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findandmodify.md#mongodb-method-db.collection.findAndModify) projection can accept [aggregation expressions and syntax.](https://www.mongodb.com/docs/manual/reference/mql/expressions.md#std-label-aggregation-expressions)

- MongoDB enforces additional restrictions with regards to projections. See [Projection Restrictions](https://www.mongodb.com/docs/manual/reference/limits.md#mongodb-limit-Projection-Restrictions) for details.

The `projection` field takes a document in the following form:

```javascript
{ field1: <value>, field2: <value> ... }
```

| Projection | Description |
| --- | --- |
| `<field>: <1 or true>` | Specifies the inclusion of a field. If you specify a non-zero integer for the projection value, the operation treats the value as `true`. |
| `<field>: <0 or false>` | Specifies the exclusion of a field. |
| `"<field>.$": <1 or true>` | Uses the [`$`](https://www.mongodb.com/docs/manual/reference/operator/projection/positional.md#mongodb-projection-proj.-) array projection operator to return the first element that matches the query condition on the array field. If you specify a non-zero integer for the projection value, the operation treats the value as `true`. Not available for [views.](https://www.mongodb.com/docs/manual/core/views.md#std-label-views-landing-page) |
| `<field>: <array projection>` | Uses the array projection operators ([`$elemMatch`](https://www.mongodb.com/docs/manual/reference/operator/projection/elemmatch.md#mongodb-projection-proj.-elemMatch), [`$slice`](https://www.mongodb.com/docs/manual/reference/operator/projection/slice.md#mongodb-projection-proj.-slice)) to specify the array elements to include. Not available for [views.](https://www.mongodb.com/docs/manual/core/views.md#std-label-views-landing-page) |
| `<field>: <aggregation expression>` | Specifies the value of the projected field. With the use of [aggregation expressions and syntax](https://www.mongodb.com/docs/manual/reference/mql/expressions.md#std-label-aggregation-expressions), including the use of literals and aggregation variables, you can project new fields or project existing fields with new values. If you specify a non-numeric, non-boolean literal (such as a literal string or an array or an operator expression) for the projection value, the field is projected with the new value, for example:`{ field: [ 1, 2, 3, "$someExistingField" ] }`; `{ field: "New String Value" }`; `{ field: { status: "Active", total: { $sum: "$existingArray" } } }`; To project a literal value for a field, use the [`$literal`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/literal.md#mongodb-expression-exp.-literal) aggregation expression, for example:`{ field: { $literal: 5 } }`; `{ field: { $literal: true } }`; `{ field: { $literal: { fieldWithValue0: 0, fieldWithValue1: 1 } } }` |

#### Embedded Field Specification

For fields in an embedded documents, you can specify the field using either:

- [dot notation](https://www.mongodb.com/docs/manual/core/document.md#std-label-document-dot-notation-embedded-fields), for example `"field.nestedfield": <value>`

- nested form, for example `{ field: { nestedfield: <value> } }`

#### `_id` Field Projection

The `_id` field is included in the returned documents by default unless you explicitly specify `_id: 0` in the projection to suppress the field.

#### Inclusion or Exclusion

A `projection` *cannot* contain *both* include and exclude specifications, with the exception of the `_id` field:

- In projections that *explicitly include* fields, the `_id` field is the only field that you can *explicitly exclude*.

- In projections that *explicitly excludes* fields, the `_id` field is the only field that you can *explicitly include*; however, the `_id` field is included by default.

For more information on projection, see also:

- [Project Fields to Return from Query](https://www.mongodb.com/docs/manual/tutorial/project-fields-from-query-results.md#std-label-read-operations-projection)

### Sharded Collections

Documents in a sharded collection can be [missing the shard key fields](https://www.mongodb.com/docs/manual/core/sharding-shard-key.md#std-label-shard-key-missing). To target a document that is missing the shard key, you can use the `null` equality match in conjunction with another filter condition (such as on the `_id` field). For example:

```javascript
{ _id: <value>, <shardkeyfield>: null } // _id of the document missing shard key
```

#### Shard Key Modification

You can update a document's shard key value unless the shard key field is the immutable `_id` field.

**Warning:**

Documents in sharded collections can be missing the shard key fields. Take precaution to avoid accidentally removing the shard key when changing a document's shard key value.

To modify the **existing** shard key value with [`db.collection.findOneAndReplace()`:](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#mongodb-method-db.collection.findOneAndReplace)

- You must run on a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos). Do not issue the operation directly on the shard.

- You must run either in a [transaction](https://www.mongodb.com/docs/manual/core/transactions.md) or as a [retryable write.](https://www.mongodb.com/docs/manual/core/retryable-writes.md)

- You must include an equality filter on the full shard key.

#### Missing Shard Key

Documents in a sharded collection can be [missing the shard key fields](https://www.mongodb.com/docs/manual/core/sharding-shard-key.md#std-label-shard-key-missing). To use [`db.collection.findOneAndReplace()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#mongodb-method-db.collection.findOneAndReplace) to set the document's **missing** shard key,

- You must run on a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos). Do not issue the operation directly on the shard.

- You must run either in a [transaction](https://www.mongodb.com/docs/manual/core/transactions.md) or as a [retryable write](https://www.mongodb.com/docs/manual/core/retryable-writes.md) if the new shard key value is not `null`.

- You must include an equality filter on the full shard key.

**Tip:**

Since a missing key value is returned as part of a null equality match, to avoid updating a null-valued key, include additional query conditions (such as on the `_id` field) as appropriate.

See also:

- [Set Missing Shard Key Fields](https://www.mongodb.com/docs/manual/core/sharding-shard-key.md#std-label-shard-key-missing)

### Transactions

[`db.collection.findOneAndReplace()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#mongodb-method-db.collection.findOneAndReplace) can be used inside [distributed transactions.](https://www.mongodb.com/docs/manual/core/transactions.md#std-label-transactions)

**Important:**

In most cases, a distributed transaction incurs a greater performance cost over single document writes, and the availability of distributed transactions should not be a replacement for effective schema design. For many scenarios, the [denormalized data model (embedded documents and arrays)](https://www.mongodb.com/docs/manual/data-modeling/embedding.md#std-label-data-modeling-embedding) will continue to be optimal for your data and use cases. That is, for many scenarios, modeling your data appropriately will minimize the need for distributed transactions.

For additional transactions usage considerations (such as runtime limit and oplog size limit), see also [Production Considerations.](https://www.mongodb.com/docs/manual/core/transactions-production-consideration.md#std-label-production-considerations)

#### Upsert within Transactions

You can create collections and indexes inside a [distributed transaction](https://www.mongodb.com/docs/manual/core/transactions.md#std-label-transactions-create-collections-indexes) if the transaction is not a cross-shard write transaction.

[`db.collection.findOneAndReplace()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#mongodb-method-db.collection.findOneAndReplace) with `upsert: true` can be run on an existing collection or a non-existing collection. If run on a non-existing collection, the operation creates the collection.

**See also:**

[Create Collections and Indexes in a Transaction](https://www.mongodb.com/docs/manual/core/transactions.md#std-label-transactions-create-collections-indexes)

#### Write Concerns and Transactions

Do not explicitly set the write concern for the operation if run in a transaction. To use write concern with transactions, see [Transactions and Write Concern.](https://www.mongodb.com/docs/manual/core/transactions.md#std-label-transactions-write-concern)

### Oplog Entries

If a `db.collection.findOneAndReplace()` operation successfully replaces a document, the operation adds an entry on the [oplog](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-oplog) (operations log). If the operation fails or does not find a document to replace, the operation does not add an entry on the oplog.

## Examples

### Replace A Document

Create a sample `scores` collection with the following documents:

```javascript
db.scores.insertMany([
   { "_id" : 1, "team" : "Fearful Mallards", "score" : 25000 },
   { "_id" : 2, "team" : "Tactful Mooses", "score" : 23500 },
   { "_id" : 3, "team" : "Aquatic Ponies", "score" : 19250 },
   { "_id" : 4, "team" : "Cuddly Zebras", "score" : 15235 },
   { "_id" : 5, "team" : "Garrulous Bears", "score" : 18000 }
]);
```

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

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

The operation returns the *original* document that has been replaced:

```javascript
{ "_id" : 3, "team" : "Aquatic Ponies", "score" : 19250 }
```

If [returnNewDocument](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-returnNewDocument) was true, the operation would return the replacement document instead.

Although multiple documents meet the filter criteria, [`db.collection.findOneAndReplace()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#mongodb-method-db.collection.findOneAndReplace) replaces only one document.

### Sort and Replace A Document

Create a sample `scores` collection with the following documents:

```javascript
db.scores.insertMany([
   { "_id" : 1, "team" : "Fearful Mallards", "score" : 25000 },
   { "_id" : 2, "team" : "Tactful Mooses", "score" : 23500 },
   { "_id" : 3, "team" : "Aquatic Ponies", "score" : 19250 },
   { "_id" : 4, "team" : "Cuddly Zebras", "score" : 15235 },
   { "_id" : 5, "team" : "Garrulous Bears", "score" : 18000 }
]);
```

By including an ascending [sort](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-sort) on the `score` field, the following example replaces the document with the lowest score among those documents that match the [filter:](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-filter)

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

The operation returns the *original* document that has been replaced:

```javascript
{ "_id" : 4, "team" : "Cuddly Zebras", "score" : 15235 }
```

See [Replace A Document](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-example-replace-document) for the non-sorted result of this command.

### Project Specific Fields in Return Document

Create a sample `scores` collection with the following documents:

```javascript
db.scores.insertMany([
   { "_id" : 1, "team" : "Fearful Mallards", "score" : 25000 },
   { "_id" : 2, "team" : "Tactful Mooses", "score" : 23500 },
   { "_id" : 3, "team" : "Aquatic Ponies", "score" : 19250 },
   { "_id" : 4, "team" : "Cuddly Zebras", "score" : 15235 },
   { "_id" : 5, "team" : "Garrulous Bears", "score" : 18000 }
])
```

The following operation uses [projection](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-projection) to only display the `team` field in the returned document:

```javascript
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:

```javascript
{ "team" : "Cuddly Zebras" }
```

### Replace Document with Time Limit

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

```javascript
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:

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

### Replace Document with Upsert

The following operation uses the [upsert](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-upsert) field to insert the replacement document if no document matches the [filter:](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-filter)

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

The operation returns the following:

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

If `returnDocument: "before"` was set, the operation would return `null` because there is no original document to return.

### Specify Collation

[Collation](https://www.mongodb.com/docs/manual/reference/collation.md#std-label-collation) allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.

Create a sample `myColl` collection with the following documents:

```javascript
db.myColl.insertMany([
   { _id: 1, category: "café", status: "A" },
   { _id: 2, category: "cafe", status: "a" },
   { _id: 3, category: "cafE", status: "a" }
]);
```

The following operation includes the [collation](https://www.mongodb.com/docs/manual/reference/method/db.collection.findoneandreplace.md#std-label-findOneAndReplace-collation) option:

```javascript
db.myColl.findOneAndReplace(
   { category: "cafe", status: "a" },
   { category: "cafÉ", status: "Replaced" },
   { collation: { locale: "fr", strength: 1 } }
);
```

The operation returns the following document:

```javascript
{ "_id" : 1, "category" : "café", "status" : "A" }
```