Order the stages of data modeling and database design from first to last: 1. Implementation, 2. Conceptual Modelling, 3. Requirements Analysis, 4. Logical Modelling, 5. Physical Model, 6. Schema Refinement.

Introduction / Context:
This sequence problem checks conceptual understanding of the typical order in database development—progressing from understanding needs to implementing an optimized physical design. Each stage feeds into the next, reducing ambiguity and improving performance and integrity.

Given Data / Assumptions:

• Stages listed: Requirements Analysis → Conceptual Modelling → Logical Modelling → Schema Refinement → Physical Model → Implementation.
• We assume a conventional, textbook order used in software engineering and database curricula.

Concept / Approach:
First gather requirements to capture domain semantics. Then create a high-level conceptual schema (e.g., ER model). Next, convert it to a logical model (e.g., relational). Apply normalization/constraints (schema refinement) to reduce redundancy and anomalies. Map to a DBMS-specific physical design. Finally, implement (DDL/DML, code, deployment).

Step-by-Step Solution:

Verification / Alternative check:
Cross-check with SDLC/DBLC references: requirements precede modelling; physical considerations and implementation occur last. The chosen sequence is standard.

Why Other Options Are Wrong:

• Any option placing Implementation before modelling is premature.
• Placing Physical before Refinement risks embedding unnormalized designs.

Common Pitfalls:
Confusing logical with physical steps; skipping schema refinement; assuming implementation can begin prior to a stable logical design.

Final Answer:
3, 2, 4, 6, 5, 1