• Goal: store each fact once instead of repeating information across rows 2:41.
  • Example of the problem: an orders table where the customer email is duplicated on every order row 2:41.
  • The fix: extract the duplicated data into two tables — a customer table holding the email in one place, and an orders table referencing it by ID; the two are then combined via foreign keys 3:09.
  • Know the normal forms: first, second, third, and fourth normal form 3:09.
  • Observation: many people no longer talk about normalization because of AI — but it remains essential 3:40.