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

Silverston c02.tex V2 - 11/21/2008 2:58am Page 52

52 Chapter 2 ■ Setting Up Roles: What Parties Do

In this table you see the PARTY, which is an ORGANIZATION, with party

id ‘‘1001,’’ with current organization name of ‘‘Matrix Ltd.’’ This PARTY

has a credit limit of ‘‘HK$100,000,’’ which is an attribute associated with

their role as a CUSTOMER. You also see a PARTY, that is a PERSON,

with party id of ‘‘1004,’’ and current first name and current last name

of ‘‘Caroline Percy.’’ This PARTY playing the role of CUSTOMER, has a

credit limit of ‘‘£3,445.’’ PARTNER is also a role that can be played by

both a person and an organization. If you examine Table 2-5 you see that

the ORGANIZATION(s) ‘‘Matrix Ltd,’’ ‘‘Card Queen Ltd,’’ and ‘‘Kantowitz

Services’’ are PARTNER(s). Also the PERSON ‘‘Leon Brinkley’’ is a PARTNER,

illustrating that a PARTNER declarative role is related to a PARTY and thus

may be related to an organization or a person.

NOTE

If numerous types of currencies are needed, there would actually be a

currency type id foreign key (that is related to a CURRENCY TYPE entity) in the

CUSTOMER to signify what type of currency applies to the credit limit .Wehavenot

included this foreign key in this example, in order to keep our focus on illustrating

the core aspects of this pattern.

The SUPPLIER role is related directly to ORGANIZATION. This relation-

ship states that ‘‘each ORGANIZATION may be acting