Interview Question

What are normal forms?

Normal forms evaluate how attributes depend on keys.

💡 Concept ✅ Quick Revision 🗃️ SQL

Answer

Normal forms are progressively stronger relational design conditions. • First normal form requires relation values to fit the relational structure used by the database. • Second and third normal forms address dependencies on keys. • Boyce-Codd normal form strengthens the determinant rule beyond third normal form.

💡 SQL Example

CREATE TABLE enrollments (student_id integer, course_id integer, grade text, PRIMARY KEY (student_id, course_id));

Result

A relation designed around its key

⚡ Quick Revision

Normal forms evaluate how attributes depend on keys.