Database Reference
In-Depth Information
Not only does subtyping reduce redundancy on a data model, but it makes it easier to com-
municate similarities across what otherwise would appear to be distinct and separate con-
cepts.
MongoDB Identity, Rolldown, Rollup = RDBMS Identity, Rolldown, Rollup (Subtype at Physical Level)
The subtyping symbol cannot exist on a physical data model, and the three ways to resolve
are Identity, Rolldown, and Rollup:
Original Logical
Identity
Rollup
Rolldown
