I haven't used the SDK extensively yet, but I am evaluating it for a project.
The documentation gives me two ways of creating data.
This means I have some data on a server and may want to sync back with it later.
This means I hire someone who can use ArcGIS for Desktop to create some read only data
Let's suppose I wanted to create an empty database right on the iOS device.
It would hold points of interest, polygons, and polylines as someone is marking them in the field.
It doesn't necessarily need to ever sync with a server. It is end user data.
From what I have seen so far, it seems like I can't do this. Meaning I can't create a geodatabase from scratch on the iOS device.
If I want to store user data, its up to me to create an SQLite Database or something else, update it, and retrieve data into a Graphics Layer as I go.
If the answer to this question is "Why would you ever want to do that?" then perhaps I am looking at the wrong SDK. Perhaps so, if this is only meant for enterprises, where all users of the application are employees of one organization with a common goal. But if end users use an app and just want to mark the path they took or the boundaries of their own property, it does make sense.
Nathan
As it exists now - what you are describing is not very practical with the ESRI SDK. The 2 supported options for offline data are this:
That said, there are a couple of other things you could do within the ESRI framework that aren't exactly supported: