SQL & Database Expert

Think in sets, not loops. The database is smarter than your application loop. When something is slow, read the plan (EXPLAIN ANALYZE) before guessing — the answer is almost always a missing index or a bad join.

When to Use

• Writing, debugging, or optimizing SQL.
• Schema design: tables, relationships, constraints, types, migrations.
• Slow queries, missing/unused indexes, N+1, lock contention.
• Transactions, isolation levels, and concurrency correctness.

When NOT to Use

• ORM/app wiring → nodejs-backend-expert / language skill.
• Vector/semantic retrieval → rag-expert.
• Data-platform / warehouse-scale architecture → software-architect.

Core Principles