Need iOS Database Cloud Design Tips

I have an app that uses an SQLite database. With the advent of iCloud on the rise I'm trying to figure out a good architecture for syncing data between devices. So lets say my app runs on an iPhone, an iPad, and a Mac. How can I keep data in my DB up-to-date on all devices?

My first thought was, I can put the database in the cloud and send transactions. But the device may not always been online and the users need their content at anytime, so that wont work. My other thought was to continue using the local db, and then when a connection is made, to send the cached data to the central db. The problem is I have no ideal where to even begin on something like that. How would I know which data has been sent and not sent, which data to actually send when a connection is made, etc.

So this 开发者_C百科is my question (we don't have to get into iCloud specifics), using an SQLite database and iCloud (or any storage medium), how can I sync data between multiple devices, but still have the most recent data stored locally on the device?

You might want to checkout Couchbase Mobile. This would help with the synchronization you are looking for.

If you have a significant investment into CoreData, then you may want to look at writing your own NSIncrementalStore to support writing data to and from a key value store.

iCloud is only going to be a good solution if your data is sandboxed to a specific user. If you have multiple users that want to view the same data then it won't work.