There are many applications that need temporal aspects in many domains.
Usually they are used for:
- specifying some periods of time
Time and Facts
Valid time of a fact:
- when the fact is (was, will be) true in the modeled reality
- independent of the transaction time
- can be past, present, future
- (link to Slowly Changing Dimensions)?
Transaction time of a fact:
- when the fact was recorded in a database
Temporal ER Diagrams
Conceptual Modeling of Temporal aspects:
How to query a temporal database?