Why Schema Design Matters
A well-designed database schema prevents data anomalies, reduces redundancy, and makes queries efficient. Spending time on schema design before writing code saves significant refactoring effort later and ensures data integrity from the start.
Primary and Foreign Keys
Primary keys uniquely identify rows. Foreign keys reference primary keys in other tables, creating relationships. Together they enforce referential integrity: you cannot reference a row that does not exist, and you cannot delete a row that is still referenced.
Normalization Basics
Normalization organizes data to minimize redundancy. First normal form eliminates repeating groups. Second normal form removes partial dependencies. Third normal form removes transitive dependencies. Most production schemas target third normal form.
ER Diagrams and Visual Modeling
Entity-Relationship diagrams represent tables as entities and foreign keys as relationships. Visual modeling helps teams communicate schema decisions, catch design issues early, and document the database structure for onboarding and maintenance.
