android - Not able to update sqlite_sequence table using RoomDatabase.query

Question

We try to update sqlite_sequence with the following code.

WeNoteRoomDatabase weNoteRoomDatabase = WeNoteRoomDatabase.instance();
weNoteRoomDatabase.query(new SimpleSQLiteQuery("UPDATE sqlite_sequence SET seq = 0 WHERE name = 'attachment'"));

However, it has no effect at all. I exam the sqlite_sequence table content using SQLite browser. The counter is not reset to 0.

If we try to run the same query manually using SQLite browser on same SQLite file, it works just fine.

Our Room database is pretty straightforward.

@Database(
    entities = {Attachment.class},
    version = 6
)
public abstract class WeNoteRoomDatabase extends RoomDatabase {
    private volatile static WeNoteRoomDatabase INSTANCE;

    private static final String NAME = "wenote";

    public abstract AttachmentDao attachmentDao();

    public static WeNoteRoomDatabase instance() {
        if (INSTANCE == null) {
            synchronized (WeNoteRoomDatabase.class) {
                if (INSTANCE == null) {
                    INSTANCE = Room.databaseBuilder(
                        WeNoteApplication.instance(),
                        WeNoteRoomDatabase.class,
                        NAME
                    )
                        .build();
                }
            }
        }

        return INSTANCE;
    }
}

Any idea what we had missed out?

---

Additional information : clearing sqlite_sequence is not working in android room

Answer 1

Room doesn't use SQLiteDatabase - but it uses SupportSQLiteDatabase, while it's source code states, that it delegates all calls to an implementation of {@link SQLiteDatabase}... I could even dig further - but I'm convinced, that this is a consistency feature and not a bug.

SQLiteDatabase.execSQL() still works fine, but with SupportSQLiteDatabase.execSQL() the same UPDATE or DELETE queries against internal tables have no effect and do not throw errors.

my MaintenanceHelper is available on GitHub. it is important that one initially lets Room create the database - then one can manipulate the internal tables with SQLiteDatabase.execSQL(). while researching I've came across annotation @SkipQueryVerification, which could possibly permit UPDATE or DELETE on table sqlite_sequence; I've only managed to perform a SELECT with Dao... which in general all hints for the internal tables are being treated as read-only, from the perspective of the publicly available API; all manipulation attempts are being silently ignored.