Capturing Time with Attributes
Figure 8-1 shows Event, whose instances are located in points of time via the attribute Event Date. It also shows Activity, which has two sets of locations in time—Scheduled and Actual. The attributes Scheduled Start Date and Scheduled End Date show when the activity is expected to happen, and the attributes Actual Start Date and Actual End Date show when it actually happened.
In support of efforts to build “dimensional” models, however, it is worth exploring (at least for a bit) the use of entity classes to represent time. The two approaches are described in detail in the next two sections.
Figure 8-1: Showing Time ...