title: How does Google Calendar do their reminders?
body: <p>I am looking at google calendar and wondering how they did their reminders.</p>
  
  <p>Currently I have just a calendar and they choose a date when they want to be notified. This does not expand very well if I want to do reminders for hours and minutes.</p>
  
  <p>So do they have like a field in their database that has like "hours,days,minutes" as a possible field?</p>
  
  <p>Or do they store dates and they just query for that date and time. So if I want a hour before my appointment(say it is Feb 3rd 3:00pm) then they just store feb 3rd 2:00pm)</p>
  
  <p>So they would store Feb 3rd 2:00 pm and on the hour just query for dates that match the current hour?</p>