Database Reference
In-Depth Information
the logical level. Determine who the validators and users will be at the logical level, and
that will determine the most useful form.
At the conceptual level, it is very possible for the validators and users to have different
technical levels and experiences; therefore, there could be more than one form for commu-
nicating the conceptual data model. At the logical level, however, you will find a majority
of the time that the same form will work well for both the validators and users.
Let's see the different forms we can choose from for both relational and dimensional per-
spectives.
For Relational
At the relational logical level, we do have the option of multiple forms. However, it would
be very difficult (but possible) to represent the LDM using business assertions or a busi-
ness sketch, both of which work well on the CDM. Variations on the relational LDM have
more to do with notation, such as using Information Engineering (IE for short), which is
the notation in this topic, versus using the UML Class Diagram, for example.
In our Account example, here is our relational LDM after normalizing, using the IE nota-
tion: