Update attribute “timestamp” reserved word

Question

I need to update the timestamp attribute in my dynamodb table using boto3 but the attribute name "timestamp" is a reserved word so it's throwing an error on the SET command.

table.update_item(

    Key={

        'id': item_id

    },

    UpdateExpression='SET timestamp = :val1', # this is the line giving the problem

    ExpressionAttributeValues={

        ":val1": new_timestamp

    }

)

"errorMessage": "An error occurred (ValidationException) when calling the UpdateItem operation: Invalid UpdateExpression: Attribute name is a reserved keyword; reserved keyword: timestamp",

Answer 1

There is a workaround using expression attribute names. 

table.update_item(

  Key={

    'id': item_id

  },

  UpdateExpression='SET #ts = :val1',

  ExpressionAttributeValues={

    ":val1": new_timestamp

  },

  ExpressionAttributeNames={

    "#ts": "timestamp"

  }

)

Check out this doc for more info Expression Attribute Names