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

Silverston c04.tex V2 - 11/21/2008 3:02am Page 185

Table 4-9 (continued)

PATTERN DESCRIPTION WHEN TO USE WHEN NOT TO USE PROS CONS

Level 3

Recursive

Pattern with

Rules

This pattern

supports the

generalized way to

maintain recursive

associations as in

the Level 3

Recursive Pattern

but also brings in

the concept of

maintaining rules

that exist for

associations. This

pattern addresses

the need to

distinguish between

classifications of a

recursive

relationship from

the rules that

govern the behavior

of the recursive

relationship.

When an enterprise

wants to flexibly

capture different

recursive associations

and accommodate

additional types of

recursive associations

that may emerge

without needing to

change the model.

When the enterprise

wants to capture the

rules that govern the

behavior of the

elements in the

structure.

For enterprises that

have a desire to move

towards rule-based

data structures.

When an enterprise does

not subscribe or need

the rules between

associations or when the

enterprise decides to

capture these rules as

association types as the

previous pattern did.

When you have specific

attributes and

relationships at different

levels in the hierarchy or

aggregation. (This could

be resolved by using

subtypes.)

When there is different

optionality between

different levels of a

hierarchy or aggregation.

Allows the capability to maintain

the rules about what is allowed

regarding the recursive

relationship instances. Facilitates

data driven applications ...