The Data Model Resource Book, Volume 3: Universal Patterns for Data Modeling

Silverston c07.tex V2 - 11/20/2008 5:44pm Page 345

Level 3 Contact Mechanism Pattern 345

CONTACT MECHANISM 2) may have one or more CONTACT MECHANISM

PURPOSE(s) and one and only one CONTACT MECHANISM USAGE. This

supports the possible need to specify an intention(s) or a reason(s) for which a

particular contact mechanism is used. For example, a telephone number may

be used for the CONTACT MECHANISM USAGE TYPE of ‘‘Business,’’ and

addresses may have multiple CONTACT MECHANISM PURPOSE TYPE(s) of

‘‘Bill to’’ (the address to send bills) and ‘‘Ship to’’ (the address to send products).

The strength of t his pattern lies in the fact that it goes some way toward

modeling contact mechanisms in a specific manner and yet still provides

a reasonable amount of flexibility to add new contact mechanisms, contact

mechanism types, p urposes, and/or usages. We would not have much problem

showing a model like this to stake holders with only a modicum of data

modeling experience.

The weaknesses of the pattern are that it is specific in some ways and

thus includes business rules that may change and that in other ways it is

not as flexible as the level 3 and level 4 patterns. For instance, each type

of contact mechanism (telecommunications number, electronic address, and

postal address) has its own data model structure and may be managed in

different ways. If the enterprise is somewhat mercurial in nature but desires

some