Databases Reference
In-Depth Information
− aggregation in the same category;
− aggregation between different categories;
− associative class;
− ternary association in the same category;
− ternary association between different categories;
− inheritance in the same category;
− inheritance between different categories; etc.
10.5.2.
Examples of derivation of semantic classes
We cannot give all the derivation rules in this topic, but
we refer the reader to the MDM modeling procedures guide,
downloadable on the MDM Alliance Group
website, to
consult them in full.
7
To illustrate these derivations, we will
now give a couple of cases taken from this guide.
10.5.2.1.
Many-to-many association spanning two data
categories
Multiple associations (one-to-many, many-to-many) are
not derived with the help of join tables, as is done in the
relational oriented approach. From an ergonomic point of
view, a specific screen for each join table would be required.
These screens are not meaningful for business users and not
very ergonomic to browse links between data. It is preferable
to directly use a multi-occurrence attribute to declare a list
of Foreign Keys as is possible with the object oriented
approach, and then to hide underlying join tables. A Model-
driven MDM is able to automatically manage these types of
multi-occurrence attributes which avoid useless bespoke
software development to hide join tables on the user
interface of an MDM.
7
. http://www.mdmalliancegroup.com. The appendix of the guide details
these derivation rules.
