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University of California, Davis

Application Development Methodology

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Development Technique Concepts

Optionality

A type of predicate condition that places constraints on whether a dependency, relationship or attribute must exist.

Optional Attribute Type

An attribute type that need not have a value for every entity of the type it describes.

Optional Relationship Membership

Membership of an entity type in a relationship, such that entities of the type may exist without participating in a pairing under the relationship.

Optional Dependency

A process dependency under which execution of one of the participating processes may execute without resulting in or following from the execution of the other.

See also: Attribute Type, Relationship Type, Dependency.