DynamoDB Batch Update

Question

Is there any API in DynamoDB to update a batch of items? There is an API to write new items in batches ( BatchWriteItem ) and update single item using UpdateItem , but is it possible to update multiple items in one call?

Answer 1

There is no batch update item API available in DynamoDB at the moment.

DynamoDB API operations list

Answer 2

I know this is an old question by now, but DynamoDB recently added a Transaction api which supports update:

Update — Initiates an UpdateItem operation to edit an existing item's attributes or add a new item to the table if it does not already exist. Use this action to add, delete, or update attributes on an existing item conditionally or without a condition.

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/transaction-apis.html

Answer 3

DynamoDBMapper.batchSave(Iterable<? extends Object> objectsToSave)我使用DynamoDBMapper.batchSave(Iterable<? extends Object> objectsToSave) 。

Answer 4

No there is no batch update currently , you can use a single update Item call and have a workflow over it like AWS SWF or AWS step functions

https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html

Answer 5

BatchWriteItem cannot update items. To update items, use the UpdateItem action. BatchWriteItem operation puts or deletes multiple items in one or more tables

Reference: http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_BatchWriteItem.html

Answer 6

我使用了一个dynamoDB更新触发器，然后我做了一个模板，告诉我我应该修改哪些项目，我把它们放在一个队列中，然后它们读取另一个队列中的消息以一一更新

Answer 7

With PartiQL you can execute batch insert and update just like SQL.

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.multiplestatements.batching.html

Answer 8

I reached this thread on similar query, hope this might help.

DynamoDB supports Batch Statement Execution which is described in documentation . This works with client object rather than resource object. Then I used the PartiQL update statement supported by DynamoDB and described here .

Python code reference looks something like this:

client = boto3.client('dynamodb')

batch = ["UPDATE users SET active='N' WHERE email='<user_email>' RETURNING [ALL|MODIFIED] [NEW|OLD] *;", "UPDATE users ..."]  # Limit to 25 per batch
request_items = [{'Statement': _stat} for _stat in batch]
batch_response = client.batch_execute_statement(Statements=request_items)

This is minimal code. You can use multi-threading to execute multiple batches at once.

Answer 9

Not exactly a batch delete but I did this in a python lambda function just now:

    import json
    import boto3

    client = boto3.client('dynamodb')

    def lambda_handler(event, context):
    
    idList = [
        "id1",
        "id2
        ...
        "id100",
    ]

    for itemID in idList:
        test = client.update_item(
                TableName='Your-Table-Name',
                Key={
                    'id': {
                        'S': itemID
                    }
                },
                UpdateExpression="set exressionToChange=:r",
                ExpressionAttributeValues={
                        ':r': {'S':'New_Value'}},
                ReturnValues="UPDATED_NEW")
        
    
    return

To get the idList, I downloaded the values in a CSV, copied them into VSCode and then did a find and replace with regex ( CMD - F then click .\* ) and set find to " .* " and replace to " $0 ", which basically replaces every line with itself in quotes and a comma

So basically before:

    id1
    id2
    id3
    ...

And after

    "id1",
    "id2",
    "id3",
    ...

Just replace " idList = [...] " with your ids, " Your-Table-Name ", " expressionToChange " and lastly, " New_Value ".

Also you will have give your lambda function permission to "Update Item" in DynamoDB or you will get an error