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db.collection.replaceOne()

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  • Definition
  • Compatibility
  • Syntax
  • Behavior
  • Examples

MongoDB with drivers

This page documents a mongosh method. To see the equivalent method in a MongoDB driver, see the corresponding page for your programming language:

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Definition

db.collection.replaceOne(filter, replacement, options)

Replaces a single document within the collection based on the filter.

Returns:A document containing:

  • A boolean acknowledged as true if the operation ran with write concern or false if write concern was disabled

  • matchedCount containing the number of matched documents

  • modifiedCount containing the number of modified documents

  • upsertedId containing the _id for the upserted document

Compatibility

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

  • MongoDB 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.

Syntax

The replaceOne() method has the following form:

db.collection.replaceOne(
   <filter>,
   <replacement>,
   {
      upsert: <boolean>,
      writeConcern: <document>,
      collation: <document>,
      hint: <document|string>
   }
)

The replaceOne() 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.

upsert

boolean

Optional. When true, replaceOne() either:

  • Inserts the document from the replacement parameter if no document matches the filter.

  • 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.

writeConcern

document

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

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.

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.

hint

document

Optional. A document or string that specifies the index to use to support the filter.

The option can take an index specification document or the index name string.

If you specify an index that does not exist, the operation errors.

For an example, see Specify hint for replaceOne.

Behavior

replaceOne() replaces the first matching document in the collection that matches the filter, using the replacement document.

upsert

If upsert: true and no documents match the filter, db.collection.replaceOne() creates a new document based on the replacement document.

If you specify upsert: true on a sharded collection, you must include the full shard key in the filter. For additional db.collection.replaceOne() behavior on a sharded collection, see Sharded Collections.

See Replace with Upsert.

Capped Collections

If a replacement operation changes the document size, the operation will fail.

Time Series Collections

You cannot use the replaceOne() method on a time series collection.

Sharded Collections

db.collection.replaceOne() attempts to target a single shard, first by using the query filter. If the operation cannot target a single shard by the query filter, it then attempts to target by the replacement document.

In earlier versions, the operation attempts to target using the replacement document.

Shard Key Requirements In Replacement Document

The replacement document does not need to include the shard key.

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.

upsert on a Sharded Collection

A db.collection.replaceOne() operation that includes upsert: true on a sharded collection must include the full shard key in the filter.

However, documents in a sharded collection can be missing the shard key fields. 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:

{ _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.replaceOne():

Missing Shard Key

Documents in a sharded collection can be missing the shard key fields. To use db.collection.replaceOne() to set the document's missing shard key, you must run on a mongos. Do not issue the operation directly on the shard.

In addition, the following requirements also apply:

Task
Requirements

To set to null

  • Requires equality filter on the full shard key if upsert: true is specified.

To set to a non-null value

  • Must be performed either inside a transaction or as a retryable write.

  • Requires equality filter on the full shard key if either:

    • upsert: true, or

    • the new shard key value belongs to a different shard.

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:

Transactions

db.collection.replaceOne() can be used inside distributed 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) 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.

Upsert within Transactions

You can create collections and indexes inside a distributed transaction if the transaction is not a cross-shard write transaction.

db.collection.replaceOne() 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.

Tip

See also:

Create Collections and Indexes in a Transaction

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.

Examples

Replace

The restaurant collection contains the following documents:

{ "_id" : 1, "name" : "Central Perk Cafe", "Borough" : "Manhattan" },
{ "_id" : 2, "name" : "Rock A Feller Bar and Grill", "Borough" : "Queens", "violations" : 2 },
{ "_id" : 3, "name" : "Empire State Pub", "Borough" : "Brooklyn", "violations" : 0 }

The following operation replaces a single document where name: "Central Perk Cafe":

try {
   db.restaurant.replaceOne(
      { "name" : "Central Perk Cafe" },
      { "name" : "Central Pork Cafe", "Borough" : "Manhattan" }
   );
} catch (e){
   print(e);
}

The operation returns:

{ "acknowledged" : true, "matchedCount" : 1, "modifiedCount" : 1 }

If no matches were found, the operation instead returns:

{ "acknowledged" : true, "matchedCount" : 0, "modifiedCount" : 0 }

Setting upsert: true would insert the document if no match was found. See Replace with Upsert

Replace with Upsert

The restaurant collection contains the following documents:

{ "_id" : 1, "name" : "Central Perk Cafe", "Borough" : "Manhattan",  "violations" : 3 },
{ "_id" : 2, "name" : "Rock A Feller Bar and Grill", "Borough" : "Queens", "violations" : 2 },
{ "_id" : 3, "name" : "Empire State Pub", "Borough" : "Brooklyn", "violations" : 0 }

The following operation attempts to replace the document with name : "Pizza Rat's Pizzaria", with upsert : true:

try {
   db.restaurant.replaceOne(
      { "name" : "Pizza Rat's Pizzaria" },
      { "_id": 4, "name" : "Pizza Rat's Pizzaria", "Borough" : "Manhattan", "violations" : 8 },
      { upsert: true }
   );
} catch (e){
   print(e);
}

Since upsert : true the document is inserted based on the replacement document. The operation returns:

{
   "acknowledged" : true,
   "matchedCount" : 0,
   "modifiedCount" : 0,
   "upsertedId" : 4
}

The collection now contains the following documents:

{ "_id" : 1, "name" : "Central Perk Cafe", "Borough" : "Manhattan", "violations" : 3 },
{ "_id" : 2, "name" : "Rock A Feller Bar and Grill", "Borough" : "Queens", "violations" : 2 },
{ "_id" : 3, "name" : "Empire State Pub", "Borough" : "Brooklyn", "violations" : 0 },
{ "_id" : 4, "name" : "Pizza Rat's Pizzaria", "Borough" : "Manhattan", "violations" : 8 }

Replace with Write Concern

Given a three member replica set, the following operation specifies a w of majority and wtimeout of 100:

try {
   db.restaurant.replaceOne(
       { "name" : "Pizza Rat's Pizzaria" },
       { "name" : "Pizza Rat's Pub", "Borough" : "Manhattan", "violations" : 3 },
       { w: "majority", wtimeout: 100 }
   );
} catch (e) {
   print(e);
}

If the acknowledgment takes longer than the wtimeout limit, the following exception is thrown:

WriteConcernError({
   "code" : 64,
   "errmsg" : "waiting for replication timed out",
   "errInfo" : {
     "wtimeout" : true,
     "writeConcern" : {
       "w" : "majority",
       "wtimeout" : 100,
       "provenance" : "getLastErrorDefaults"
     }
   }
})

The following table explains the possible values of errInfo.writeConcern.provenance:

Provenance
Description

clientSupplied

The write concern was specified in the application.

customDefault

The write concern originated from a custom defined default value. See setDefaultRWConcern.

getLastErrorDefaults

The write concern originated from the replica set's settings.getLastErrorDefaults field.

implicitDefault

The write concern originated from the server in absence of all other write concern specifications.

Specify Collation

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.replaceOne(
   { category: "cafe", status: "a" },
   { category: "cafÉ", status: "Replaced" },
   { collation: { locale: "fr", strength: 1 } }
);

Specify hint for replaceOne

Create a sample members collection with the following documents:

db.members.insertMany([
   { "_id" : 1, "member" : "abc123", "status" : "P", "points" :  0,  "misc1" : null, "misc2" : null },
   { "_id" : 2, "member" : "xyz123", "status" : "A", "points" : 60,  "misc1" : "reminder: ping me at 100pts", "misc2" : "Some random comment" },
   { "_id" : 3, "member" : "lmn123", "status" : "P", "points" :  0,  "misc1" : null, "misc2" : null },
   { "_id" : 4, "member" : "pqr123", "status" : "D", "points" : 20,  "misc1" : "Deactivated", "misc2" : null },
   { "_id" : 5, "member" : "ijk123", "status" : "P", "points" :  0,  "misc1" : null, "misc2" : null },
   { "_id" : 6, "member" : "cde123", "status" : "A", "points" : 86,  "misc1" : "reminder: ping me at 100pts", "misc2" : "Some random comment" }
])

Create the following indexes on the collection:

db.members.createIndex( { status: 1 } )
db.members.createIndex( { points: 1 } )

The following update operation explicitly hints to use the index { status: 1 }:

Note

If you specify an index that does not exist, the operation errors.

db.members.replaceOne(
   { "points": { $lte: 20 }, "status": "P" },
   { "misc1": "using index on status", status: "P", member: "replacement", points: "20"},
   { hint: { status: 1 } }
)

The operation returns the following:

{ "acknowledged" : true, "matchedCount" : 1, "modifiedCount" : 1 }

To view the indexes used, you can use the $indexStats pipeline:

db.members.aggregate( [ { $indexStats: { } }, { $sort: { name: 1 } } ] )

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