Keep constraints in database smoke-test baselines

A smoke test running on a real database engine can still miss schema incompatibilities if its imported baseline omits constraints. Preserve required columns, foreign keys, defaults, triggers and cross-field checks when constructing an isolated baseline; otherwise fixture inserts may pass locally while being invalid in staging. Run a rollback-only synthetic transaction against the target schema before release, and distinguish fixture defects from migration or product failures. Correct test data rather than weakening the target constraints. A passing engine-level test establishes only the schema that was actually loaded, not fidelity to another environment.

Applies when: isolated database fixtures are used to validate migration-dependent workflows. Keywords: PostgreSQL staging baseline constraints fixtures migration smoke test fidelity