To distinguish a couple of terms within the calender_framework, the following definitions will apply:

• Entry: An entry is one row in the table tx_calendar_entry and defines all "metadata" of one or many entries. Due to connection with one ore more recurrences one entry can result in many events.
• Event: An event is a concrete representation of the combination of either an entry without any recurrences or the combination of an entry with it recurrences. Every event is stored in the table tx_calendar_event as an own row with only the concrete start and end of this event and the connection to the entry (to have an easy to follow association to all the metadata like "title" or "description").
• Recurrence: When an event takes place more than once, this is represented by the recurrences. In the table tx_calendar_recurrences every row is connected to only one entry and can contain information like "every 2nd day", "every monday" or "every 3rd week"
• Deviation: If you have a single event during a recurrence that deviates from the default event. A typical deviation might be a changed room for a gathering or a different start and end time.
• Exception: Time periods within a recurrence when the events don't take place. Think of closed gymnasiums during the holidays or vacation of a trainer.
  •  Exceptions can be used for multiple events ("all courses will be canceled during the holidays") and can have an own recurrence ("every year all courses will be canceled on halloween").
  •  Exception vs. Deviation: If you have an event, that is canceled for some reason (exception), but have a deviation matching the same date, the the deviation will take precedence. Think about the following use case: "During the holidays we have to cancel all courses in the regular location (exception). Therefore we evade to another location (deviation)."
• Exception groups: For convenience reasons, it is possible to group exceptions in useful units. E.g. group all holidays in one group to apply this group to multiple entries. Please note, that this groups act only as a kind of shrink wrap for exceptions with no additional function. So every time, an exception group is used within the calender_framework the list of associated exceptions is returned instead.