Enhanced ERD Flashcards
A subgrouping of the entities in an entity type that has attributes distinct from those in other subgrouping
Subtype
A genetic entity type that has a relationship with one or more subtypes
Supertype
An instance of a subtype is also an instance of the?
supertype
______ entities inherit values of all attributes of the supertype
subtype
Relationships at the _________ level indicate that all subtypes will participate in the relationship
supertype
The instances of a __________ may participate in a relationship unique to that subtype.
subtype
The process of defining a more general entity type from a set of more specialized entity types.
Generalization (BOTTOM-UP)
The process of defining one or more subtypes of the supertype and forming supertype/subtype relationships.
Specialization (TOP-DOWN)
Whether an instance of a supertype must also be a member of at least one subtype.
Completeness Constraints
Total specialization Rule
double line
Partial Specialization Rule
single line
Whether an instance of a supertype may simultaneously be a member of two (or more) subtypes
Disjointness Constraints
An instance of the supertype can be only ONE of the subtypes
Disjoint Rule
An instance of the supertype could be more than one of the subtypes
Overlap Rule
An attribute of the supertype whose values determine the target subtype(s)
Subtype Discriminator
a simple attribute with alternative values to indicate the possible subtypes
Disjoint
A composite attribute whose subparts pertain to different subtypes. Each subpart contains a boolean value to indicate whether or not the instance belongs to the associated subtype
Overlapping
Set of one or more entity types and associated relationships grouped into a single abstract entity type.
Entity cluster
Derived from other knowledge, often in the form of a formula using attribute values.
Derivation-rule
Expressing static structure. Includes attributes, relationships, and definitions.
Structural assertion-rule
Expressing contraints/control of organizational actions.
Action assertion-rule
an object on which actions are limited
Anchor Object
an object influencing the ability to perform an action on another business rule
Corresponding Objects
