Question

I have an App using sqlite. On first start, I copy the .db file into NSDocumentDirectory (so that I can make updates to it). In later versions, I plan to add new data to this database. How can I make sure, that with every application update (but not with every app start) the newest copy of this DB will be copied to NSDocumentDirectory?

Thanks

-Konstantin

Answer 1

I have a constant that I increment with new builds, say kDatabaseVersion.

At startup, I check for the following:

• Does the DB exist in the Documents directory? If not, copy it. This probably means a first launch has occurred.

• If the DB does exist, check the version from the constant against a NSUserDefaults entry with the same key. If the constant is greater, copy the database over. If not, do not. Update NSUserDefaults accordingly.

Of course, if the database contains data from your users also, you have to work out how to migrate that to a new data store. If you are using Core Data, you might even consider multiple persistent stores to separate user and default data.