In a supertype–subtype hierarchy, which type of entity has its association to the supertype governed by a discriminator attribute defined on the supertype?

Introduction / Context:Generalization/specialization modeling uses a discriminator on the supertype to decide which specialized path an instance follows. This is a cornerstone of clean modeling for heterogeneous categories.

Given Data / Assumptions:

• A discriminator attribute exists on the supertype (e.g., CustomerType = 'Retail'/'Wholesale').
• Instances are routed to the correct specialized entity based on the discriminator value.
• We seek the name of the specialized entity affected by the discriminator.

Concept / Approach:The subtype is the specialized entity that inherits common attributes from the supertype and adds subtype-specific attributes. The discriminator value determines which subtype applies for a given supertype instance.

Step-by-Step Solution:

Verification / Alternative check:ERD notations often annotate the supertype with a discriminator attribute and connect to subtypes via exclusive or overlapping constraints.

Why Other Options Are Wrong:Supertype entity: Hosts the discriminator, not governed by it. Archetype / Instance / Associative entity: Not the standard terms for specialization levels in ER modeling.

Common Pitfalls:Putting the discriminator on each subtype—by definition it belongs on the supertype to choose among subtypes.

Final Answer:Subtype entity