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Bulk Write Operations
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Overview
Consider a scenario in which you want to insert a document into a collection, update multiple other documents, then delete a document. If you use individual methods, each operation requires its own database call. This guide shows you how to use bulk write operations to perform multiple write operations in a single database call.
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.
Define the Write Operations
For each write operation you want to perform, create an instance of one of the following operation classes:
InsertOne
UpdateOne
UpdateMany
ReplaceOne
DeleteOne
DeleteMany
Then, pass a list of these instances to the bulk_write()
method.
The following sections show how to create and use instances of the preceding classes.
Insert Operations
To perform an insert operation, create an instance of InsertOne
and specify
the document you want to insert.
The following example creates an instance of InsertOne
:
operation = pymongo.InsertOne( { "name": "Mongo's Deli", "cuisine": "Sandwiches", "borough": "Manhattan", "restaurant_id": "1234" } )
To insert multiple documents, create an instance of InsertOne
for each document.
Update Operations
To update a document, create an instance of UpdateOne
and pass in
the following arguments:
A query filter that specifies the criteria used to match documents in your collection
The update operation you want to perform. For more information about update operations, see the Field Update Operators guide in the MongoDB Server manual.
UpdateOne
updates the first document that matches your query filter.
The following example creates an instance of UpdateOne
:
operation = pymongo.UpdateOne( { "name": "Mongo's Deli" }, { "$set": { "cuisine": "Sandwiches and Salads" }}, )
To update multiple documents, create an instance of UpdateMany
and pass in
the same arguments. UpdateMany
updates all documents that match your query
filter.
The following example creates an instance of UpdateMany
:
operation = pymongo.UpdateMany( { "name": "Mongo's Deli" }, { "$set": { "cuisine": "Sandwiches and Salads" }}, )
Replace Operations
A replace operation removes all fields and values of a specified document and
replaces them with new ones. To perform a replace operation, create an instance
of ReplaceOne
and pass it a query filter and the fields and values you want
to store in the matching document.
The following example creates an instance of ReplaceOne
:
operation = pymongo.ReplaceOne( { "restaurant_id": "1234" }, { "name": "Mongo's Pizza", "cuisine": "Pizza", "borough": "Brooklyn", "restaurant_id": "5678" } )
To replace multiple documents, you must create an instance of ReplaceOne
for each document.
Delete Operations
To delete a document, create an instance of DeleteOne
and pass in a
query filter specifying the document you want to delete. DeleteOne
removes
only the first document that matches your query filter.
The following example creates an instance of DeleteOne
:
operation = pymongo.DeleteOne({ "restaurant_id": "5678" })
To delete multiple documents, create an instance of DeleteMany
and pass in a
query filter specifying the document you want to delete. DeleteMany
removes
all documents that match your query filter.
The following example creates an instance of DeleteMany
:
operation = pymongo.DeleteMany({ "name": "Mongo's Deli" })
Call the bulk_write()
Method
After you define a class instance for each operation you want to perform,
pass a list of these instances to the bulk_write()
method.
By default, the method runs the operations in the order
they're defined in the list.
The following example performs multiple write operations by using the
bulk_write()
method:
operations = [ pymongo.InsertOne( { "name": "Mongo's Deli", "cuisine": "Sandwiches", "borough": "Manhattan", "restaurant_id": "1234" } ), pymongo.InsertOne( { "name": "Mongo's Deli", "cuisine": "Sandwiches", "borough": "Brooklyn", "restaurant_id": "5678" } ), pymongo.UpdateMany( { "name": "Mongo's Deli" }, { "$set": { "cuisine": "Sandwiches and Salads" }}, ), pymongo.DeleteOne( { "restaurant_id": "1234" } ) ] results = restaurants.bulk_write(operations) print(results)
BulkWriteResult({'writeErrors': [], 'writeConcernErrors': [], 'nInserted': 2, 'nUpserted': 0, 'nMatched': 2, 'nModified': 2, 'nRemoved': 1, 'upserted': []}, acknowledged=True)
If any of the write operations fail, PyMongo raises a
BulkWriteError
and does not perform any further operations.
BulkWriteError
provides a details
attribute that includes the operation
that failed, and details about the exception.
Note
When PyMongo runs a bulk operation, it uses the write_concern
of the
collection in which the operation is running. The driver reports all write
concern errors after attempting all operations, regardless of execution order.
Customize Bulk Write Operations
The bulk_write()
method optionally accepts additional
parameters, which represent options you can use to configure the bulk write
operation. If you don't specify any additional options, the driver does not customize
the bulk write operation.
Property | Description |
---|---|
ordered | If True , the driver performs the write operations in the order
provided. If an error occurs, the remaining operations are not
attempted.If False , the driver performs the operations in an
arbitrary order and attempts to perform all operations.Defaults to True . |
bypass_document_validation | Specifies whether the operation bypasses document-level validation. For more
information, see Schema
Validation in the MongoDB
Server manual. Defaults to False . |
session | An instance of ClientSession . For more information, see the API
documentation. |
comment | A comment to attach to the operation. For more information, see the delete command
fields guide in the
MongoDB Server manual. |
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. |
The following example calls the bulk_write()
method from the preceding example, with the ordered
option set
to False
:
results = restaurants.bulk_write(operations, ordered=False)
If any of the write operations in an unordered bulk write fail, PyMongo reports the errors only after attempting all operations.
Note
Unordered bulk operations do not guarantee order of execution. The order can differ from the way you list them to optimize the runtime.
Return Value
The bulk_write()
method returns a BulkWriteResult
object. The
BulkWriteResult
object contains the following properties:
Property | Description |
---|---|
acknowledged | Indicates if the server acknowledged the write operation. |
bulk_api_result | The raw bulk API result returned by the server. |
deleted_count | The number of documents deleted, if any. |
inserted_count | The number of documents inserted, if any. |
matched_count | The number of documents matched for an update, if applicable. |
modified_count | The number of documents modified, if any. |
upserted_count | The number of documents upserted, if any. |
upserted_ids | A map of the operation's index to the _id of the upserted documents, if
applicable. |
Additional Information
To learn how to perform individual write operations, see the following guides:
API Documentation
To learn more about any of the methods or types discussed in this guide, see the following API Documentation: