Create / interact with a batch of updates / deletes.
Batches provide the ability to execute multiple operations in a single request to the Cloud Datastore API.
See https://cloud.google.com/datastore/docs/concepts/entities#batch_operations
Classes
Batch
Batch(client)An abstraction representing a collected group of updates / deletes.
Used to build up a bulk mutation.
For example, the following snippet of code will put the two save
operations and the delete operation into the same mutation, and send
them to the server in a single API request:
.. testsetup:: batch
import uuid
from google.cloud import datastore
unique = str(uuid.uuid4())[0:8]
client = datastore.Client(namespace='ns{}'.format(unique))
.. doctest:: batch
>>> entity1 = datastore.Entity(client.key('EntityKind', 1234))
>>> entity2 = datastore.Entity(client.key('EntityKind', 2345))
>>> key3 = client.key('EntityKind', 3456)
>>> batch = client.batch()
>>> batch.begin()
>>> batch.put(entity1)
>>> batch.put(entity2)
>>> batch.delete(key3)
>>> batch.commit()
You can also use a batch as a context manager, in which case
commit will be called automatically if its block exits without
raising an exception:
.. doctest:: batch
>>> with client.batch() as batch:
... batch.put(entity1)
... batch.put(entity2)
... batch.delete(key3)
By default, no updates will be sent if the block exits with an error:
.. doctest:: batch
>>> def do_some_work(batch):
... return
>>> with client.batch() as batch:
... do_some_work(batch)
... raise Exception() # rolls back
Traceback (most recent call last):
...
Exception
.. testcleanup:: txn
with client.batch() as batch:
batch.delete(client.key('EntityKind', 1234))
batch.delete(client.key('EntityKind', 2345))
| Parameter | |
|---|---|
| Name | Description |
client |
Client
The client used to connect to datastore. |