onUpgrade database - oldVersion - newVersion

Question

I am using this DataBaseHelper.class and I am stuck on the onUpgrade()-method. I do not know how to figure out what the version number of the database is. I could set the ve

Answer 1

// Do you need this?
private static int DATABASE_VERSION = 2;

Yes, you need this. (Even better, make it final too.)

This tells the database helper what the latest version of the database schema is. This should be fixed in your app code, and incremented whenever you alter the schema.

When your app starts up, the helper does a check at runtime that your code's idea of the latest version is the same as the version which was active when the database was last created or upgraded. (This is what db.getVersion() is for.) If the numbers don't match, then the helper knows that the stored database is out-of-date with respect to your application code, and so it runs the upgrade routine.

It looks as if you're not creating the database from scratch, but importing an existing database from your assets. When you do this initial import, this is the time at which to make sure the stored version matches your code's version; either apply it directly to the database file in your assets, or, if you're sure the database file in your assets matches the code, then you call setVersion(DATABASE_VERSION).

In any case, you shouldn't be trying to modify the version numbers in the onUpgrade() routine. This is only ever called if the versions don't match, and all you're supposed to do here is make whatever changes are needed to bring the database up-to-date. The helper will manage the storing of the new version number once the upgrade is complete.