sqlite updatefunction not working

heyo, i have setup my database properly and allready inserted data to it, now i want to update the data but it doesnt work

As example one method of my code:

 cv.put(KEY_MINI_COUNT, newValue);



            return db.update(DATABASE_TABLE, cv, null, null);

I get a "0" from the return statement, which means 0 rows are update, and no exeptions. I have only 1 row in my database(dont need more). I have tried exchanging the first "null" with a "_id = 1" but it didnt work either. does someone know why its not updating?