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db.collection.replaceOne()

Definition

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

New in version 3.2.

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

The replaceOne() method has the following form:

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

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.
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.

New in version 3.4.

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

Behavior

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

If upsert: true and no documents match the filter, replaceOne() creates a new document based on the replacement document. See Replace with Upsert.

Capped Collections

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

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

WriteConcernError({
   "code" : 64,
   "errInfo" : {
      "wtimeout" : true
   },
   "errmsg" : "waiting for replication timed out"
})

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

);