GATE CS 2026 Set 2 Q5 — ER-model

The question is based on the Three-Schema Architecture (also known as the ANSI-SPARC architecture) in Database Management Systems (DBMS). Let us map each schema level in set $\mathbf{T}$ to its corresponding representation in set $\mathbf{S}$:

1. I. Logical Schema $\rightarrow$ N. Relations:
   The logical (or conceptual) schema describes the logical structure of the entire database, including entities, attributes, relationships, and constraints, while hiding physical storage details. In a relational DBMS, this structure is represented using Relations (tables).
2. II. Physical Schema $\rightarrow$ M. File organization and indexes:
   The physical (or internal) schema describes how the data is actually stored on physical storage devices. It specifies details such as file organization, record formats, and access paths (indexes).
3. III. External Schema $\rightarrow$ L. Views:
   The external schema (or view level) describes the part of the database that is visible to specific user groups. It is implemented using Views to present customized subsets of data to different users.

Thus, the correct matching is: $$\mathrm{I}-\mathrm{N}, \quad \mathrm{II}-\mathrm{M}, \quad \mathrm{III}-\mathrm{L}$$ This corresponds to Option C.