The datastore maintains calendars , which are collections of iCal components. The components include events , to-dos , journal entries , and alarms . A calendar can be owned by one or more users . User attributes are maintained by an external mechanism. Calendars have calendar sets, which allow multiple calendar sources to be aggregated into a single calendar for display purposes.
Calendars also use links.
Links are similar to calendar sets, but allow a more granular selection of events to overlay. For example, suppose that a convention center maintains a calendar of all the conventions to be held in its facilities. A user may be interested in one of the conventions, but not in all of them. In this case, the user can add an event into a personal calendar as a link to the event of interest in the convention calendar. Any change to the event in the convention center's calendar will be reflected in the linked copy.