Normalization means organising data in tables so that the same data is not stored in many places. It saves space and avoids mistakes when data changes.
Form
Rule
1NF
Every cell has one value (no lists in a cell). Every row is unique
2NF
1NF, and every column depends on the whole primary key
3NF
2NF, and columns do not depend on other non-key columns
Example: instead of writing the course name in every student row, we keep a courses table and store only a course_id in students. If the name changes, you change it in one place. See MySQL JOINs.
