OpenOrCreateDatabase in a ListFragment

Hi i have a fragment and i want to display some information of a specific column this code works perfectly with an activity but nothing work in a listfragment especially db=openOrCreateDatabase here is the activity code :

public class MainActivity extends ListActivity {
ListView listView;
ArrayList<String> arrayList = new ArrayList<String>();
ArrayAdapter<String> adapter;
SQLiteDatabase db;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    listView = getListView();

    adapter = new ArrayAdapter<String>(MainActivity.this,
            android.R.layout.simple_list_item_1, arrayList);
    listView.setAdapter(adapter);
    db=openOrCreateDatabase("StudentDB", Context.MODE_PRIVATE, null);
    db.execSQL("CREATE TABLE IF NOT EXISTS student(rollno VARCHAR,name VARCHAR,marks VARCHAR);");
    db.execSQL("INSERT INTO student VALUES('hello@aol.com', 'Jeff1', 'Bath')");
    db.execSQL("INSERT INTO student VALUES('hello@aol.com', 'Jeff2', 'Bath')");
    db.execSQL("INSERT INTO student VALUES('hello@aol.com', 'Jeff3', 'Bath')");
    Cursor cursor = db.rawQuery("SELECT * FROM student", null);
    //  Toast.makeText(myContext, ""+cursor.getCount(), Toast.LENGTH_LONG).show();
    if (cursor.moveToFirst())
    {
        do
        {
            arrayList.add(cursor.getString(0));

        } while (cursor.moveToNext());
    }

}

and here is what i did for the listfragment it 's working until i add the database :

    public class F1_fr extends ListFragment {
   View rootview;
    TextView textView1;
    ArrayAdapter<String> aa;
    ArrayList<String> arrayList = new ArrayList<String>();
    SQLiteDatabase db;



    @Override

    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        rootview=inflater.inflate(R.layout.f1_lay,container,false);




        textView1=(TextView)rootview.findViewById(R.id.textView1);



         aa = new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_list_item_1,  arrayList);

        setListAdapter(aa);


        return rootview;

    }


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        db=SQLiteDatabase.openOrCreateDatabase("StudentDB", null);
        db.execSQL("CREATE TABLE IF NOT EXISTS student(rollno VARCHAR,name VARCHAR,marks VARCHAR);");
        db.execSQL("INSERT INTO student VALUES('hello@aol.com', 'Jeff1', 'Bath')");
        db.execSQL("INSERT INTO student VALUES('hello@aol.com', 'Jeff2', 'Bath')");
        db.execSQL("INSERT INTO student VALUES('hello@aol.com', 'Jeff3', 'Bath')");
        Cursor cursor = db.rawQuery("SELECT * FROM student", null);
        //  Toast.makeText(myContext, ""+cursor.getCount(), Toast.LENGTH_LONG).show();
        if (cursor.moveToFirst())
        {
            do
            {
                arrayList.add(cursor.getString(0));

            } while (cursor.moveToNext());
        }
    }

So i'am asking your help to make it work with a listfragment ,thanks in advance