A Student table stores several phone numbers in one column as a comma-separated string such as ‘0300-1111111, 0321-2222222’. Which normal form does this violate?
Correct answer B. First normal form
Explanation
1NF requires every attribute value to be atomic, meaning a single indivisible value from its domain. A comma-separated list packs many values into one field, so queries must parse strings and updates to one number become awkward. 2NF and 3NF deal with dependencies on keys and are only considered once 1NF holds. The usual fix is a separate StudentPhone(student_id, phone) table.
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