delete all items DynamoDB using Python

Question

How can I delete all items from DynamoDB using python (boto3)?

I'm trying to do that:

scan = table.scan()
with table.batch_writer() as batch:
  for each in scan['Items']:
    batch.delete_item(Key=each)

But give me this error:

botocore.exceptions.ClientError: An error occurred (ValidationException) when calling the BatchWriteItem operation: The provided key element does not match the schema

Answer 1

While I agree that dropping the table and recreating it is much more efficient, there may be cases such as when many GSI's or Trigger events are associated with a table and you don't want to have to re-associate those. The script below will iterate over the scan to handle large tables (each scan call will return 1Mb worth of keys) and use the batch function to delete all items in the table.

import boto3
dynamo = boto3.resource('dynamodb')

def truncateTable(tableName):
    table = dynamo.Table(tableName)
    
    #get the table keys
    tableKeyNames = [key.get("AttributeName") for key in table.key_schema]

    #Only retrieve the keys for each item in the table (minimize data transfer)
    projectionExpression = ", ".join('#' + key for key in tableKeyNames)
    expressionAttrNames = {'#'+key: key for key in tableKeyNames}
    
    counter = 0
    page = table.scan(ProjectionExpression=projectionExpression, ExpressionAttributeNames=expressionAttrNames)
    with table.batch_writer() as batch:
        while page["Count"] > 0:
            counter += page["Count"]
            # Delete items in batches
            for itemKeys in page["Items"]:
                batch.delete_item(Key=itemKeys)
            # Fetch the next page
            if 'LastEvaluatedKey' in page:
                page = table.scan(
                    ProjectionExpression=projectionExpression, ExpressionAttributeNames=expressionAttrNames,
                    ExclusiveStartKey=page['LastEvaluatedKey'])
            else:
                break
    print(f"Deleted {counter}")
            
truncateTable("YOUR_TABLE_NAME")

Answer 2

I found a solution! I just mount the key with my table Id and search Id (compId) and It's worked :)

scan = table.scan()
with table.batch_writer() as batch:
    for each in scan['Items']:
        batch.delete_item(
            Key={
                'uId': each['uId'],
                'compId': each['compId']
            }
        )