Does “entity class” mean a collection (set) of entity instances characterized by the same structure (attributes and identifier) defined for that class?

Introduction / Context:
An entity class (or entity type) defines the attributes and identifier that all its instances share. Thinking of “class” as a set of similarly structured instances helps bridge conceptual models to logical schemas and later to tables and rows.

Given Data / Assumptions:

• Entity class/type provides a template (name, attributes, identifier).
• Instances conform to the template and differ by values.
• Relationships connect instances across classes according to business rules.

Concept / Approach:
Treat the entity class as the schema-level definition and each entity as a data-level occurrence. This allows consistent constraints, domains, and keys across all instances and informs table design and normalization decisions.

Step-by-Step Solution:
Define the entity class (e.g., Product with ProductID, Name, Price). Assert that every Product instance has those attributes and respects domains. Use the identifier to ensure uniqueness across the set of instances. Relate the class to others via relationships (e.g., Product–Supplier).

Verification / Alternative check:
Ensure that constraints (NOT NULL, CHECK, UNIQUE) apply uniformly across all instances, consistent with the class definition.

Why Other Options Are Wrong:
Restricting the concept to weak entities or OO models is unnecessary; “entity class” is a general ER term.

Common Pitfalls:
Blurring instance-level facts with class-level definitions; inconsistent attribute usage across instances.

Final Answer:
Correct