update app database regularly without needing an app update

I am working on a WP7 app that contains CategoryGroups Categories Products

The rows for each of these entities are populated on first run of the application.

The issues is that when the app gets published, the rows in each of the entities will change (added, deleted, modified). I would like some suggestions on how I should handle this? Any pointers to existing code samples will be great?

I am using an object oriented database to store my entities. The app also allows the user to add their own entities (which get added to the database as personalized (flagged) entities). One solution I was thinking was to read an xml file from the server and then loop through the database entries and make the necessary modifications in the database. So, on the first run, all the entities will just get inserted. On subsequent runs, i开发者_运维技巧f the version number attribute in xml is different, then the system populated data is reloaded from xml but the user data is preserved.

Also, maybe only check for the new xml file on the server when internet connection is available and only periodically (like every 2 weeks).

Any other suggestions are welcome. If there is a simpler, cleaner way - please share.

Pratik

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I think it's fair to say that this question has nothing to do with WP7 and everything to do with finding an efficient way to to compute and deliver update deltas.

Timestamp your items. When requesting an update, specify the time of last update. You server can trivially query for items newer than this and return a delta. At the client (ie in the phone) it is not necessary to store a last update time because you can simply add one second to the most recent timestamp in the items present on the phone.