Database Design Patterns That Scale

Good database design is the foundation of any performant application. Here are the patterns I've found most valuable across years of working with SQL Server and MySQL.

Indexing Strategy

Indexes are your first line of defense against slow queries. But more indexes aren't always better — each write operation must update every index.

-- Composite index for common query pattern
CREATE INDEX idx_orders_user_date
ON orders (user_id, created_at DESC);

-- Covering index to avoid table lookups
CREATE INDEX idx_posts_status_cover
ON posts (status)
INCLUDE (title, created_at, author_id);

Normalization vs Denormalization

Third Normal Form (3NF) is the sweet spot for most applications. But for read-heavy workloads, strategic denormalization can dramatically improve performance.

Connection Pooling

Always use connection pooling. Both SQL Server and MySQL drivers support it natively — make sure it's properly configured for your workload.

Key Takeaways

- Index what you query, not everything

- Use EXPLAIN to understand query plans

- Denormalize only when you've measured the need

- Connection pooling is not optional in production