Replace Documents
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Overview
In this guide, you can learn how to use PyMongo to perform a replace operation on a document in a MongoDB collection. A replace operation performs differently than an update operation. An update operation modifies only the specified fields in a target document. A replace operation removes all fields in the target document and replaces them with new ones.
To learn more about update operations, see the Update Documents guide.
Sample Data
The examples in this guide use the sample_restaurants.restaurants
collection
from the Atlas sample datasets. To learn how to create a
free MongoDB Atlas cluster and load the sample datasets, see the
Get Started with PyMongo tutorial.
Replace Operation
You can perform a replace operation in MongoDB by using the replace_one()
method.
This method removes all fields except the _id
field from the first document that
matches the search criteria. It then inserts the fields and values you specify into the
document.
Required Parameters
The replace_one()
method requires the following parameters:
A query filter document, which determines which documents to replace. For more information about query filters, see the Query Filter Documents section in the MongoDB Server manual.
A replace document, which specifies the fields and values to insert in the new document.
Replace One
The following example uses the replace_one()
method to replace the fields and values of a
document with a name
field value of "Pizza Town"
:
restaurants = database["restaurants"] query_filter = {"name" : "Pizza Town"} replace_document = { "name" : "Mongo's Pizza", "cuisine" : "Pizza", "address" : { "street" : "123 Pizza St", "zipCode" : "10003" }, "borough" : "Manhattan" } result = restaurants.replace_one(query_filter, replace_document)
Important
The values of _id
fields are immutable. If your replacement document specifies
a value for the _id
field, it must match the _id
value of the existing document.
Customize the Replace Operation
The replace_one()
method optionally accepts additional
parameters, which represent options you can use to configure the replace
operation. If you don't specify any additional options, the driver does not customize
the replace operation.
Property | Description |
---|---|
upsert | Specifies whether the replace operation performs an upsert operation if no
documents match the query filter. For more information, see the upsert
statement
in the MongoDB Server manual. Defaults to False |
bypass_document_validation | Specifies whether the replace operation bypasses document validation. This lets you
replace documents that don't meet the schema validation requirements, if any
exist. For more information about schema validation, see Schema
Validation in the MongoDB
Server manual. Defaults to False . |
collation | Specifies the kind of language collation to use when sorting
results. For more information, see Collation
in the MongoDB Server manual. |
hint | Gets or sets the index to scan for documents.
For more information, see the hint statement
in the MongoDB Server manual. |
session | An instance of ClientSession . |
let | A Map of parameter names and values. Values must be constant or closed
expressions that don't reference document fields. For more information,
see the let statement in the
MongoDB Server manual. |
comment | A comment to attach to the operation. For more information, see the insert command
fields guide in the
MongoDB Server manual. |
The following code uses the replace_one()
method to find the first document where the
name
field has the value "Food Town"
, then replaces this document
with a new document named "Food World"
. Because the upsert
option is
set to True
, the driver inserts a new document if the query filter doesn't
match any existing documents.
restaurants = database["restaurants"] query_filter = {"name" : "Food Town"} replace_document = { "name" : "Food World", "cuisine" : "Mixed", "address" : { "street" : "123 Food St", "zipCode" : "10003" }, "borough" : "Manhattan" } result = restaurants.replace_one(query_filter, replace_document, upsert = True)
Return Value
The replace_one()
method returns an UpdateResult
object. The UpdateResult
type contains the following properties:
Property | Description |
---|---|
matched_count | The number of documents that matched the query filter, regardless of
how many were updated. |
modified_count | The number of documents modified by the update operation. If an updated
document is identical to the original, it is not included in this
count. |
raw_result | The raw result document returned by the server. |
upserted_id | The ID of the document that was upserted in the database, if the driver
performed an upsert. Otherwise None . |
Additional Information
To learn more about creating query filters, see the Specify a Query guide.
API Documentation
To learn more about any of the methods or types discussed in this guide, see the following API documentation: