问Android数据库升级问题

EN

public class WIMProvider extends ContentProvider {

    private static final int DATABASE_VERSION = 2;

    private DatabaseHelper mOpenHelper;

    // ..... code .....

    private static class DatabaseHelper extends SQLiteOpenHelper {

        private Context mContext;

        public DatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
            mContext = context;
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

            if (oldVersion == 1) {
                db.execSQL("ALTER TABLE TCategory ADD COLUMN fiDefault integer DEFAULT 0");
                oldVersion++;
            }
            if (oldVersion == 2) {
                db.execSQL("ALTER TABLE TCategory ADD COLUMN fsIcon nvarchar(50)");
                oldVersion++;
            }
        }
}