Redesign hygiene: during a database redesign, is it typical to maintain at least two separate copies of the schema (for example, development and test) rather than working only against production?

Introduction / Context:
Safe schema redesign requires separate environments to prototype changes, validate data migrations, and run regression tests without risking production integrity or availability.

Given Data / Assumptions:

• Separate dev, test/QA, and production environments exist.
• CI/CD processes apply migrations progressively.
• Representative data is available in non-prod for realistic testing.

Concept / Approach:
Multiple schema copies support iterative design: developers experiment in dev; QA validates in test with realistic volumes; only then are changes promoted to prod. This approach reduces risk and surfaces performance or compatibility issues early.

Step-by-Step Solution:
Clone schema (and anonymized data) into dev and test.Apply migration scripts; run unit/integration/performance tests.Fix issues; repeat until stable.Promote to production via controlled release.

Verification / Alternative check:
Most SDLC best practices mandate ≥2 non-prod environments before production deployment.

Why Other Options Are Wrong:
Relying solely on production is unsafe. ORM usage or hosting model does not remove the need for separate environments.

Common Pitfalls:
Testing with unrealistic data sizes; skipping data migration rehearsals; inadequate rollback plans.

Final Answer:
Correct — keep at least dev and test schema copies during redesign.