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- db.collection.replaceOne()
db.collection.replaceOne()¶
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Definition¶
-
db.collection.
replaceOne
(filter, replacement, options)¶ Replaces a single document within the collection based on the filter.
The
replaceOne()
method has the following form: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 thefilter
. - Replaces the document that matches the
filter
with thereplacement
document.
MongoDB will add the
_id
field to the replacement document if it is not specified in either thefilter
orreplacement
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 Read Concern/Write Concern/Read Preference.
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:
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
astrue
if the operation ran with write concern orfalse
if write concern was disabled matchedCount
containing the number of matched documentsmodifiedCount
containing the number of modified documentsupsertedId
containing the_id
for the upserted document
- Inserts the document from the
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.
Transactions¶
db.collection.replaceOne()
supports multi-document transactions.
If the operation results in an upsert, the collection must already exist.
Do not explicitly set the write concern for the operation if run in a transaction. To use write concern with transactions, see Read Concern/Write Concern/Read Preference.
Important
In most cases, multi-document transaction incurs a greater performance cost over single document writes, and the availability of multi-document transaction 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 multi-document transactions. For additional transactions usage considerations (such as runtime limit and oplog size limit), see also Production Considerations.
Examples¶
Replace¶
The restaurant
collection contains the following documents:
The following operation replaces a single document where
name: "Central Perk Cafe"
:
The operation returns:
If no matches were found, the operation instead returns:
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:
The following operation attempts to replace the document with
name : "Pizza Rat's Pizzaria"
, with upsert : true
:
Since upsert : true
the document is inserted based on the
replacement
document. The operation returns:
The collection now contains the following documents:
Replace with Write Concern¶
Given a three member replica set, the following operation specifies a
w
of majority
and wtimeout
of 100
:
If the acknowledgement takes longer than the wtimeout
limit, the following
exception is thrown: