US Patent 7499942 Modeling recurring events in a data store

Time-related properties may be modeled independent of a base object. Rather than storing time properties with the object, they may be stored independently. A given object may be stored once, even if it has a recurrent time property. The description of a “meeting,” for example, may be stored once. Each occurrence of that object over time may be stored in a “timeslot” (object <foo> occurs at time ‘t’ on day ‘d’). If it is a recurring property, recurrence information may be stored independently. “Exception” information may be stored independently as well.