global-skills/skills/database-design/SKILL.md

name, description, scope

name	description	scope
database-design	Design schemas, migrations, and queries or diagnose query performance using the project database and measured workload.	global

Database design

1. Inspect the engine/version, existing models, migration tooling, queries, expected volume, concurrency, and durability requirements.
2. Define keys, constraints, relationships, deletion behavior, and transaction boundaries. Bind values using driver parameters; validate dynamic identifiers separately. Keep consistency-sensitive checks and writes in one transaction.
3. Design indexes around actual filters, joins, and ordering; inspect query plans when optimizing. Cardinality alone does not determine whether an index helps.
4. Bound interactive list queries using product-appropriate limits. Use stable keyset ordering for deep pagination; exports and internal batch jobs may stream larger datasets. Do not impose pagination on every query.
5. Use the existing migration mechanism and plan data/backward compatibility. Verify affected reads, constraints, and migration behavior under shared verification.

SQLite when applicable

WAL can improve concurrent reads/writes on supported local storage; it is not a universal engine choice or a promise of a particular write rate. Choose FULL for power-loss durability, or NORMAL only when its durability tradeoff is acceptable. Enable foreign keys per connection, use explicit connection lifetimes, and choose busy handling/checkpoint behavior for the workload. Consult the installed version's pragma documentation for exact semantics.