Extract stable document fields through an additive migration
The model needs relational owner and created-at columns while old records and clients still use JSON.
- Focused work estimate
- 3h 30m + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Migrations · Compatibility
Estimated field mix
- Database engineering80%
- Backend20%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
A fictional records portal stores every property in one JSON column. Queries disagree about missing values, and malformed records make ordinary filters fail.
Setup prerequisites
- Create synthetic document metadata with malformed and legacy versions.
- Use migrations and a local query API.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
Acceptance criteria
- Add nullable relational fields and required target constraints.
- Keep original metadata available during migration.
- Reject contradictory dual representations on new writes.
Implementation constraints
- Use a migration file and explicit data conversion rules.
Verification to include
- Insert a consistent bridge record.
- Provide different owner identities in columns and JSON and reject the write.
Deliverables
- Schema expansion and bridge validation
Rollout and recovery
Deploy additive schema before readers; rollback bridge code while retaining untouched metadata.
Value of the work
For the engineer: Practice relational/JSON boundaries, versioned validation and query semantics.
For the team: Review a data model that stays inspectable while allowing controlled variation.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.