Saving Data Locally and Remotely (Syncing)
When data is entered, it ultimately needs to be saved remotely on a server. I do want the app to work if there is no data connection at the time also, so I need to save everything locally on the phone too. The app can then sync with the server when it gets a connection.

This brings up a little issue. I'm used to saving everything on the server and then getting the records back with id's generated from the server for them. If there is no connection, the app will save locally to the phone but not the server. When syncing with the server, I don't see a way for the phone to know when a record comes back which locally record it's associated with. There isn't enough unique data to figure this out.

What is the best way to handle this?

One way I've been thinking is to change the id of the records to a GUID and let the phone set the id. This way, all records will have an id locally, and when saving to the server, it should still be a unique id.

I'd like to know what other people have been doing, and what works and what doesn't from experience.
Saving Data Locally and Remotely (Syncing)
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When data is entered, it ultimately needs to be saved remotely on a server. I do want the app to work if there is no data connection at the time also, so I need to save everything locally on the phone too. The app can then sync with the server when it gets a connection.

This brings up a little issue. I'm used to saving everything on the server and then getting the records back with id's generated from the server for them. If there is no connection, the app will save locally to the phone but not the server. When syncing with the server, I don't see a way for the phone to know when a record comes back which locally record it's associated with. There isn't enough unique data to figure this out.

What is the best way to handle this?

One way I've been thinking is to change the id of the records to a GUID and let the phone set the id. This way, all records will have an id locally, and when saving to the server, it should still be a unique id.

I'd like to know what other people have been doing, and what works and what doesn't from experience.