Why interviewers ask this
It tests database design knowledge.
How to approach it
Explain reducing redundancy and update problems by splitting data into related tables, and mention normal forms briefly.
Example answer
Normalization organizes data so each fact is stored once. For instance, instead of repeating a customer address in every order row, I keep customers in one table and reference them by ID.
What a weak answer sounds like
Normalization is making the database better.
It is vague, has no example and gives the interviewer nothing to remember.
Common mistake
Not explaining why normalization is useful.
Follow-up questions to expect
- What are the first three normal forms?
- When would you denormalize?
- What is a foreign key?
How to practise
Take a messy spreadsheet and normalise it into three tables on paper.
Use this as a pattern, not a script. Answer in your own words with your own examples.