Update Function Doesn't Throw DoesNotExist Error

[brian-t-otts]

The documentation says that the update() function should throw a DoesNotExist error, but it always seems to throw an UpdateError. Here's a link to the method documentation: https://pynamodb.readthedocs.io/en/latest/api.html#pynamodb.models.Model.update.

Would it be possible to get this looked into? Thanks!

[ikonst]

Looking at the UpdateItem API:

Edits an existing item's attributes, or adds a new item to the table if it does not already exist.

There's no "update existing" mode. You can condition on the item already existing with condition=MyModel.my_id.exists() but the condition failing would manifest in an UpdateError (I don't believe we get to know which one of the conditions failed).

Therefore probably the right course of action is to update the documentation to remove the mention of update raising DoesNotExist.