sql-development_skill

Overview

This skill helps design efficient database schemas, write optimized SQL queries, and manage data operations following database best practices. It focuses on schema normalization, index strategy, and performant CRUD patterns. The goal is reliable, maintainable, and high-performance data access for production systems.

How this skill works

I inspect application data models and query patterns, propose normalized schemas, and recommend primary/foreign keys and constraints. I analyze slow queries with EXPLAIN, suggest index strategies, and rewrite queries to reduce scans and avoid N+1 issues. I also provide migration guidance and testing approaches using realistic data volumes.

When to use it

• Designing or refactoring a database schema
• Optimizing slow or frequently-run queries
• Planning and applying index strategies
• Creating safe database migrations
• Reducing data redundancy and enforcing constraints

Best practices

• Define primary keys, foreign keys, and appropriate constraints
• Index columns used in JOINs, WHERE, ORDER BY, and GROUP BY
• Avoid SELECT *; list only required columns
• Use prepared statements or parameterized queries to prevent SQL injection
• Analyze queries with EXPLAIN and test with realistic data volumes

Example use cases

• Designing a task management schema with proper indexes and status tracking
• Optimizing a slow report query by adding composite indexes and rewriting joins
• Refactoring an API to eliminate N+1 queries and batch fetch related records
• Creating migration scripts that add/remove columns with minimal downtime
• Reviewing query plans and proposing index changes for high-traffic tables