Distinguish the conceptual, logical, and physical schemas, and name the SDLC phase that produces each.

Answer

Conceptual = technology-independent description of all data (Analysis); logical = conceptual mapped to a specific technology, e.g. relational tables/keys (logical Design); physical = how the logical schema is stored by a specific DBMS — file org, indexes (physical Design).

The separation across levels is exactly what gives data independence — a physical change need not ripple up to the logical schema or programs.