quantumquirkxyz Contract
- Input: domain requirements and access patterns.
- Output: schema and migration artifact.
- Side effects: none (design only; no DB writes during skill run unless user explicitly runs migration scripts separately).
- Dependencies: none.
- Stop condition: schema and migration plan complete.
- Risk: low.
- Boundary: schema design and migration plan; no direct DB changes unless user executes scripts separately.
Relational DB Design
Design a relational database schema — entities, relations, keys, indexes, constraints — with normalisation, query patterns, and migration planning.
When to use
- The user wants a database schema designed or audited.
- A new feature requires a model change.
- A migration needs sequencing.
Process
- Identify entities and relationships (1:1, 1:N, N:M).
- Normalise to 3NF (at least); denormalise only for read-heavy patterns with justification.
- Define primary / foreign / composite / candidate keys; state uniqueness constraints.
- Design indexes for the query workload — primary access path, search patterns, reporting queries.
- Define constraints: NOT NULL, CHECK, UNIQUE, foreign-key actions (ON DELETE / UPDATE).
- Migration plan: backward-compatible steps (add column, backfill, change constraint, drop old column / table); rollback steps.
- Performance: explain plan for critical queries; estimate size and growth.
- Deliver — artifact: schema diagram (text/table), entity descriptions, index justification, constraints, and migration script sequence.