Intent

Replace each genitive case with an appropriate verb to form a complete predicate.

Motivation

The genitive case often hides a substantive verb that can be revealed through appropriate analysis or inference. Exposing the (sometimes hidden) relationships between domain elements increases the value of domain analysis, offering the opportunity for further modeling and steps toward a more natural and comprehensive solution design.

Applicability

Use possession discovery when

• you discover a noun phrase with a possessive form (‘s), or
• you discover a noun phrase that uses a possessive preposition (of).

Considerations

The genitive (possessive) case relates two nouns or noun phrases. The genitive case uses the preposition of or the possessive form (‘s) to indicate ownership, possession, property, containment, or aggregation.

Identifying the nature of the relationship hidden by use of the genitive case helps to determine whether to model the elements of the relationship as separate objects, or whether the object of the relationship should become an attribute of the subject, a component of the composite. The importance of these distinctions to domain modeling has been raised by others.

Consequences

Once you’ve discovered the kind of relationship hidden by the genitive case, you’ll want to extract it using an isolated verb. However, if the genitive phrase is embedded in another clause, you’ll need to use clause summary to extract it. Fortunately, summarizing such clauses as descriptive noun phrases is usually straightforward. Consider the following examples:

category	example
possession	the hair of the dog ==> a dog has hair (as a physical attribute)
property	the color of a car ==> a car body has a color (as a property)
ownership	a library‘s book ==> a library owns a book
containment	drums of chemicals ==> a drum contains a chemical
aggregation	a bicycle‘s pedals ==> a bicycle has pedals (as parts)