SQL

Query, design, migrate, and optimize SQL databases. Use when working with SQLite, PostgreSQL, or MySQL — schema design, writing queries, creating migrations, indexing, backup/restore, and debugging slow queries. No ORMs required.

Write efficient PostgreSQL queries and design schemas with proper indexing and patterns.

Plan, operate, and recover relational databases with schema governance, safe migrations, backup drills, and incident response playbooks.

Design Cassandra tables, write efficient queries, and avoid distributed database pitfalls.

Database Engineering Mastery covers schema design, indexing, query optimization, and migration for PostgreSQL, MySQL, SQLite, supporting OLTP/OLAP workloads.

Write efficient Prisma queries, design schemas, and avoid common ORM pitfalls.