ObjectBox, how to drop-everything migration on conflicts?

Question

In my case saved data can be cleaned without fear in case of model changes, there is a better way to do this ?

private val dataSource = try {
    MyObjectBox.builder().androidContext(context).build().boxFor(XXXX::class)
} catch (e: Exception) {
    BoxStore.deleteAllFiles(context, BoxStoreBuilder.DEFAULT_NAME)
    MyObjectBox.builder().androidContext(context).build().boxFor(XXXX::class)
}

I'm wondering if there is such a thing as this: https://developer.android.com/reference/android/arch/persistence/room/RoomDatabase.Builder#fallbackToDestructiveMigration()

score 1 · Accepted Answer · answered May 18 '22 at 11:07

This approach is a bit hacky, but why not!? I mean, if you don't care about loosing existing data...

Two possible refinements I can suggest:

boxFor() should be outside the try because any error here would be unrelated to model changes.
Instead of Exception, you could be more specific. E.g. DbSchemaException for model related exceptions, or as an "in-between" solution, DbException for catching any DB-related exceptions (including DbSchemaException).

So, to adapt your code it could look like this:

private val store = try {
    MyObjectBox.builder().androidContext(context).build()
} catch (e: DbSchemaException) {
    BoxStore.deleteAllFiles(context, BoxStoreBuilder.DEFAULT_NAME)
    MyObjectBox.builder().androidContext(context).build()
}
private val box = store.boxFor(XXXX::class)

good point, i will use your code with DbException if where isn't other solution. like ROOM fallbackToDestructiveMigration — Alessandro Scarozza, May 18 '22 at 12:15

ObjectBox, how to drop-everything migration on conflicts?

1 Answers1