Factless Accident Events
We earlier described factless fact tables as the collision of keys at a point in space and time. In the case of an automobile insurer, you can record literal collisions using a factless fact table. In this situation, the fact table registers the many-to-many correlations between the loss parties and loss items, or put in laymen’s terms, all the correlations between the people and vehicles involved in an accident.
Two new dimensions appear in the factless fact table shown in Figure 16-11. The loss party captures the individuals involved in the accident, whereas the loss party role identifies them as passengers, witnesses, legal representation, or some other capacity. As we did in Chapter 3: Retail Sales, we include a fact that is always valued at 1 to facilitate counting and aggregation. This factless fact table can represent complex accidents involving many individuals and vehicles because the number of involved parties with various roles is open-ended...