What is it
Database design is the process of structuring a database to accurately represent real-world data and relationships while supporting efficient querying — covering entity-relationship modelling, choosing appropriate keys, and balancing normalisation against query performance.
Why it matters
Good database design decisions made early in a project prevent enormous amounts of pain later — a poorly designed schema leads to slow queries, data inconsistency, and expensive rework, making this one of the highest-leverage skills in software development.
Exam tip
Always draw an entity-relationship diagram before writing any table creation code — sketching entities, attributes, and relationships visually first catches design flaws that are much harder to spot once you're already deep in SQL syntax.
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