How to update SQLite database in fragment? Android

I display my database in listview in a fragment. Also I add a new data in a dialog. I have a little problem about updating database when I add some data in dialog and when I return to my fragment which displays my database in listview, there is no data which I add recently. When I close and reopen my app, data displays in listview.

I guess you understand my issue.

Here is my codes. This my fragment where I display my database in listview.

public class JanuaryFragment extends Fragment {

private DB myDB;
private List<Person> people;
private ListView listView;
private Context mContext;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.january_fragment, container, false);

    mContext = getActivity();

    myDB = new DB(mContext);
    people = getThisMonthsPeople( myDB.getAllPeople());

    listView = (ListView)rootView.findViewById(R.id.listViewOfBirthdays);
    listView.setAdapter(new PersonAdapter(mContext, people));

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            EditBirthdayDialog dialog = new EditBirthdayDialog(mContext, people.get(position));
            dialog.show();
        }
    });

    return rootView;
}

public List<Person> getThisMonthsPeople(List<Person> allPeople){
    List<Person> resultPeople = new LinkedList<Person>();
    for(int i = 0; i< allPeople.size(); i++){
        if(allPeople.get(i).getMonth()==1){
            resultPeople.add(allPeople.get(i));
        }
    }
    return resultPeople;
}
}

Here is my dialog which add a new data.

public class AddBirthdayDialog extends Dialog {

private Context context;
String name;
String sname;
private int day;
private int month;
private int year;

final EditText textName;
final EditText textSname;
final DatePicker birthDate;

private DB myDB;
private SQLiteDatabase database;
private Person person = new Person();

public AddBirthdayDialog(Context context) {
    super(context);
    this.context = context;

    setCanceledOnTouchOutside(false);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.addbirthday_layout);


    myDB = new DB(context);


    textName = (EditText) findViewById(R.id.editTextname);
    textSname = (EditText) findViewById(R.id.editTextsname);
    birthDate = (DatePicker) findViewById(R.id.datePicker);



    Button cancelButton = (Button) findViewById(R.id.cancelbutton);
    cancelButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            clearForm();
            dismiss();

        }
    });

    Button save = (Button) findViewById(R.id.buttonadd);
    save.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            name = textName.getText().toString();
            sname = textSname.getText().toString();

            day = birthDate.getDayOfMonth();
            month = birthDate.getMonth()+1;
            year = birthDate.getYear();
            final String dayStr = String.valueOf(day);
            final String monthStr = String.valueOf(month+1);
            final String yearStr = String.valueOf(year);

            person.setName(name);
            person.setSname(sname);
            person.setDay(day);
            person.setMonth(month);
            person.setYear(year);
            person.setDateStr(dayStr + "/" + monthStr + "/" + yearStr);

            myDB.addBirthday(person);
            clearForm();
            dismiss();
        }
    });
}

public void setDatePicker(int day, int month, int year){
    birthDate.updateDate(day,month,year);
}

//Cleans the form
public void clearForm(){
    textName.setText("");
    textSname.setText("");
    textSname.setText("");
}
}

Thank you in advance!