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

Silverston c07.tex V2 - 11/20/2008 5:44pm Page 385

Contact Mechanism Pattern with Geographic Boundary 385

an associated entry in the GEOGRAPHIC BOUNDARY TYPE entity. The

GEOGRAPHIC BOUNDARY subtypes are related to each other via the

GEOGRAPHIC BOUNDARY ASS OCIATION entity. For example,

COUNTRY (‘‘United States of America,’’ ‘‘Australia’’) may contain S T ATE

(‘‘New York’’, ‘‘New South Wales’’), or COUNTRY (‘‘Italy’’) may contain

REGION (Calabria). These associations can be typed, for example, the ‘‘New

York’’ to ‘‘United States of America’’ association could be considered a ‘‘State

Country relationship’’ in the GEOGRAPHIC BOUNDARY ASSOCIATION

TYPE entity. Another example would be how the ‘‘Calabira’’ to ‘‘Italy’’

association could be a ‘‘Region Country relationship.’’

NOTE

The subtypes within GEOGRAPHIC BOUNDARY may or may not be

subtypes in your data model, depending on your application. If there are no

attributes or relationships that are specific to these subtypes, then we recommend

not including them as subtypes and only as instances of GEOGRAPHIC BOUNDARY

TYPE.

Each CONTACT MECHANISM may be referencing one or more

CONTACT MECHANISM BOUNDARY(s), which are each for a

GEOGRAPHIC BOUNDARY. The n each GEOGRAPHIC BOUNDARY may be

from and to other GEOGRAPHIC BOUNDARY(s) through t he GEOGRAPHIC

BOUNDARY ASSOCIATION that is classified by a GEOGRAPHIC

BOUNDARY ASSOCIATION TYPE. For example, Table 7-16 shows ...