iphone table view delete entry and update app engine db

I have a tableview with data, that i post to the app engine database. Whenever i delete an entry in the table, i want to delelte the item in the app engine database as well. How do i know which entry to delete?

I was thinking of this:

for every item i save in the GAE store, i make a reference to a model with the iphone unique device id. for every item i save in the GAE store, i insert a UUID for iphone db & app engine db.

So my query would be something like this ex:

del item where unique device id = ####
and item UUID = ####

I dont want to login to app engine, thats why i am using the unique device id.

My only concern is performance, GAE has to lookup device id and the UUID, i dont know if this wil be a problem?

Best solution would be if just could delete it by its db.Key(), but i dont know how to do that, because when i post the data to GAE i dont know what key it genera开发者_如何学Cted.

Could anyone give me some advice?

The approach you suggest is reasonable. If you specify the UUID as your key name, you can delete it directly. To create an entity with a key name, do:

MyEntity(key_name=a_string, ...)

To delete an entity by key name (without fetching it first), do:

db.delete(db.Key.from_path("MyEntity", a_string))

There's no need to have both a UUID and a device ID - the UUID is sufficient to ensure uniqueness across all devices.