I'm relatively new to Core Data. I'm trying to piece together a small application using the technology, mainly for learning purposes. What I have is this: I have a group of people. Each person carries a phone. Each person answers their phone on a schedule, which they submit in advance. None of the schedules are synchronized (i.e., one person's schedule does not affect any other person's schedule; there may be several people all answering the phone at any given time, or there may be no people answering their phones). What I would like to do is display in a Table View a list of all currently active people. In other words, look at the object "Bob," and if "Bob" has volunteered to answer his phone from 3pm to 6pm, and it's currently 4pm, then show "Bob" in the list. If it's currently 230pm, don't show "Bob" in the list (until 3pm, then add him to the list). Lather, rinse, repeat for all people objects. Twist: How to handle days of the week (i.e., "Bob" answers the phone from 3pm to 6pm Monday thru Wednesday, but only from 3pm to 5pm Thursday and not at all on Friday, Saturday or Sunday). As ever, thanks in advance for any advice you can offer.