CIT 381 Chapter 5, Database Systems: Design, Implementation, and
Management
1. Completeness Constraint: A constraint that specifies whether each entity supertype occurrence must
also be a member of at least on subtype. The completeness constraint can be partial or total.
2. Design Trap: A problem that occurs when a relationship is improperly or incompletely identified and therefore
is represented in a way that is not consistent with the real world. The most common design trap is known as a fan trap.
3. Disjoint Subtype: In specialization hierarchy, a unique and non-overlapping subtype entity set.
4. EER Diagram (EERD): Th entity relationship diagram resulting from the application of extended entity
relationship concepts that provide additional semantic content in the ER model.
5. Entity Cluster: A "virtual" entity type used to represent multiple entities and relationships in the ERD. An entity
cluster is formed by combining multiple interrelated entities into a single abstract entity object. An entity cluster is
1/2
Management
1. Completeness Constraint: A constraint that specifies whether each entity supertype occurrence must
also be a member of at least on subtype. The completeness constraint can be partial or total.
2. Design Trap: A problem that occurs when a relationship is improperly or incompletely identified and therefore
is represented in a way that is not consistent with the real world. The most common design trap is known as a fan trap.
3. Disjoint Subtype: In specialization hierarchy, a unique and non-overlapping subtype entity set.
4. EER Diagram (EERD): Th entity relationship diagram resulting from the application of extended entity
relationship concepts that provide additional semantic content in the ER model.
5. Entity Cluster: A "virtual" entity type used to represent multiple entities and relationships in the ERD. An entity
cluster is formed by combining multiple interrelated entities into a single abstract entity object. An entity cluster is
1/2
