In the ANSI/SPARC three-schema architecture, which of the following is NOT one of the three schema components?

Introduction / Context:
The ANSI/SPARC three-schema architecture explains how database systems separate concerns across internal, conceptual, and external layers. Knowing which layers are official helps clarify where physical storage, logical design, and user views fit.

Given Data / Assumptions:

• The classic three schemas are internal, conceptual, and external.
• “Programming schema” is not a formal part of this model.
• The question asks for the option that does not belong.

Concept / Approach:
The internal schema handles physical storage structures and access paths. The conceptual schema defines the overall logical structure for the organization. External schemas (subschemas) define user/application-specific views. There is no “programming schema” in the ANSI/SPARC model.

Step-by-Step Solution:

Verification / Alternative check:
Any foundational DBMS text lists exactly these three layers; none mentions a programming schema as a fourth layer.

Why Other Options Are Wrong:
Internal schema: Correct physical layer.
Conceptual schema: Correct enterprise logical model.
External schema: Correct user/application view layer.

Common Pitfalls:
Confusing application programming interfaces with the ANSI/SPARC layers.

Final Answer:
programming schema.