Databases · Junior · Question 38 of 75

Which table violates first normal form (1NF)?

1users(id, name) and phones(user_id, phone)
✓Correct answer: users(id, name, phones) where phones holds '111, 222, 333'
3users(id, name, email) with a unique email

Explanation

1NF requires atomic values. A list in one cell can't be indexed, validated or joined properly; move it to a separate table.

Further reading

Wikipedia: Database normalization ↗

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