Database design is the systematic process of structuring data within a relational database to minimize redundancy, ensure integrity, and optimize query performance—foundational to virtually every application that persists data. Whether building an e-commerce platform or a clinical trial management system, effective database design determines whether your application scales gracefully or collapses under load. At its core, database design balances normalization (eliminating redundancy through structured decomposition) with denormalization (strategic redundancy for performance), guided by principles like ACID guarantees, proper indexing, and constraint enforcement. The most critical concept to internalize: your schema is a contract—once data accumulates and systems depend on it, structural changes become exponentially costlier, making upfront design decisions disproportionately impactful.