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

Silverston c04.tex V2 - 11/21/2008 3:02am Page 169

Level 3 Recursive Pattern 169

In the first two rows of Table 4-7 you can see two ‘‘version’’ relationships of

WORK EFFORTS, where ‘‘Create Initial Scope Statement’’ has now become a

version of the work effort called ‘‘Develop Statement of Work and Scope’’ and

‘‘Discover Target Requirements’’ was changed to a version of this work effort

called of ‘‘Develop Requirements Specifications.’’ You also see in Table 4-7

that the WORK EFFORT ASSOCIATION can have a ‘‘Precedent’’ association

type also, with ‘‘Create Mapping Template’’ needing to happen before ‘‘Create

Mapping.’’

InTable4-5yousawtheworkbreakdownstructureforthe‘‘EnterpriseData

Warehouse’’ proje ct. This work effort structure can also easily be accommo-

dated by the WORK EFFORT ASSOCIATION entity. You see in Table 4-7 that

‘‘Mapping’’ is a lower level work effort of ‘‘Enterprise Data Warehouse,’’ and

you also see that ‘‘Mapping’’ has two work efforts within it, namely, ‘‘Create

Mapping Template’’ and ‘‘Create Mapping.’’

Some issues do arise because of the ‘‘generalized’’ nature of this pat-

tern. In Figure 4-9 in the previous section, you saw that the relation-

ship names to the WORK EFFORT BREAKDOWN and WORK EFFORT

PRECEDENT were very descriptive. For example, the relationships between

WORK EFFORT and WORK EFFORT PRECEDENT stated that ‘‘each WORK

EFFORT may be dependent on one or more WORK EFFORT ...