In conceptual and logical data modeling, do entities use identifiers while tables (relational implementations) use keys to uniquely distinguish records?

Introduction / Context:
Models progress from conceptual (entities) to logical/physical (tables). The vocabulary shifts slightly: entities have identifiers; tables implement identifiers as keys (primary, candidate, alternate). Grasping the mapping ensures a clean translation from ER diagrams to relational schemas.

Given Data / Assumptions:

• An “identifier” uniquely identifies an entity instance in the conceptual model.
• A “key” (primary key or candidate key) uniquely identifies a row in a table.
• We are talking about standard relational design conventions.

Concept / Approach:
The identifier of an entity becomes a table key when the model is implemented. For example, the entity Student may have StudentNumber as its identifier; in the relational schema, table STUDENT implements PRIMARY KEY (StudentNumber). Foreign keys implement inter-entity relationships.

Step-by-Step Solution:
Confirm that an entity requires an identifier to avoid ambiguity among instances. Map entities to tables and identifiers to keys. Define PKs and FKs accordingly (e.g., STUDENT(StudentNumber PK), ENROLMENT(StudentNumber FK)). Validate uniqueness and referential integrity in the DBMS.

Verification / Alternative check:
Review any normalization exercise: identifiers logically precede the key choice; the PK chosen enforces uniqueness of rows that represent entity instances.

Why Other Options Are Wrong:
“Incorrect” ignores standard terminology alignment. NoSQL and dimensional qualifiers are distractions; the statement concerns core relational mapping.

Common Pitfalls:
Treating business identifiers and surrogate keys as the same; a surrogate key is a technical key that may implement or supplement the conceptual identifier.

Final Answer:
Correct