我正在实施此操作，以对数据库进行新的问题更新，但是它不起作用，更新后数据库仍然相同，我的意思是，我有10个问题，然后我又添加了2个问题，之后数据库仍然有10个问题。我在做什么错了？

DbHelper.java

public void addQuestions(List<Question> questions) {
        db = getwritabledatabase();

        for (Question question : questions) {
            insertQuestion(question);
        }
    }

Main.java

List<Question> questions = new ArrayList<Question>();
QuizDbHelper.getInstance(this).addQuestions(questions);

DbHelper.java

private void insertQuestion(Question question) {
        Contentvalues cv = new Contentvalues();
        cv.put(QuestionsTable.COLUMN_QUESTION,question.getQuestion());
        cv.put(QuestionsTable.COLUMN_OPTION1,question.getOption1());
        cv.put(QuestionsTable.COLUMN_OPTION2,question.getOption2());
        cv.put(QuestionsTable.COLUMN_OPTION3,question.getOption3());
        cv.put(QuestionsTable.COLUMN_ANSWER,question.getanswer());
        db.insert(QuestionsTable.TABLE_NAME,null,cv);
    }

public ArrayList<Question> getallQuestions() {
        ArrayList<Question> questionList = new ArrayList<>();
        db = getReadableDatabase();
        Cursor c = db.rawQuery("SELECT * FROM " + QuestionsTable.TABLE_NAME,null);

        if (c.moveToFirst()) {
            do {
                Question question = new Question();
                question.setQuestion(c.getString(c.getcolumnIndex(QuestionsTable.COLUMN_QUESTION)));
                question.setOption1(c.getString(c.getcolumnIndex(QuestionsTable.COLUMN_OPTION1)));
                question.setOption2(c.getString(c.getcolumnIndex(QuestionsTable.COLUMN_OPTION2)));
                question.setOption3(c.getString(c.getcolumnIndex(QuestionsTable.COLUMN_OPTION3)));
                question.setanswer(c.getInt(c.getcolumnIndex(QuestionsTable.COLUMN_ANSWER)));
                questionList.add(question);
            } while (c.moveToNext());
        }

        c.close();
        return questionList;
    }