Android Notification at Date and Time present in a Database

Question

I have a Database having various date and time entries. I want to make an android application that matches all the date time entries with the current date and time and gives a notification when the entry matches. What would be the best way to do this? I want that the loop should work every 6 hours. Should I create a service.?

I have a TimeAlarm class

public class TimeAlarm extends BroadcastReceiver {

// NotificationManager nm;

@Override
public void onReceive(Context context, Intent intent) {
    NotificationCompat.Builder nb = new NotificationCompat.Builder(context);
    Date dt = new Date();

    int hours = dt.getHours();
    int minutes = dt.getMinutes();
    int seconds = dt.getSeconds();
    String str = hours + ":" + minutes + ":" + seconds;
    System.out.print(str);
    TestAdapter tat = new TestAdapter(context);
    tat.createDatabase();
    tat.open();
    Cursor mcurr = tat.getTestData();
    if (mcurr != null)
        do {
            String data = mcurr.getString(4);
            if (str.equals(data))
                ;
            {
                nb.setContentTitle("New Episode Released");

                nb.setContentText(mcurr.getString(1));
                nb.setSmallIcon(R.drawable.ic_launcher);
                nb.setAutoCancel(true);
                NotificationManager nm = (NotificationManager) context
                        .getSystemService(Context.NOTIFICATION_SERVICE);
                final Intent notificationIntent = new Intent(context,
                        TitleScreen.class);
                notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP
                        | Intent.FLAG_ACTIVITY_NEW_TASK);
                final PendingIntent contentIntent = PendingIntent
                        .getActivity(context, 0, notificationIntent, 0);
                nb.setContentIntent(contentIntent);
                Notification notification = nb.getNotification();
                nm.notify(0, notification);

            }

        } while (mcurr.moveToNext());
    tat.close();
}
}

Then I have this ShowSeries Class where i have called this TimeAlarm class

public void remind() {
    Intent intent = new Intent(this, TimeAlarm.class);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0,
            intent, PendingIntent.FLAG_ONE_SHOT);
    am.set(AlarmManager.RTC_WAKEUP,
            System.currentTimeMillis() + (5 * 1000), pendingIntent);
}

And this TestAdapter Class through which I am accessing database.

public Cursor getTestData() {
    try {
        System.out.println("inside gettestdata");
        String sql = "SELECT * FROM TV";
        System.out.println("query passed");
        Cursor mCur = mDb.rawQuery(sql, null);
        if (mCur != null) {
            mCur.moveToFirst();
        }
        return mCur;
    } catch (SQLException mSQLException) {
        Log.e(TAG, "getTestData >>" + mSQLException.toString());
        throw mSQLException;
    }
}

The remind function is called when I press a specific button. but after that it should work continuously after every 6 hours. After using this code, I am only getting results when I press that button.