db.collection.replaceOne()¶

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Definition
Behavior
Examples

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: copy 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.

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:

copy

{ "_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":

copy

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

The operation returns:

copy

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

If no matches were found, the operation instead returns:

copy

{ "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:

copy

{ "_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:

copy

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:

copy

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

The collection now contains the following documents:

copy

{ "_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:

copy

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:

copy

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:

copy

{ _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:

copy

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

);

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