Multiple choice technology databases

Which constraint can only be applied at the column level?

  1. Primary Key

  2. Check

  3. Not Null

  4. Unique
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

NOT NULL constraints must be specified at the column level because they directly define whether a single column can accept null values. Other constraints like PRIMARY KEY, UNIQUE, and CHECK can be defined at either the column level or the table level (especially when spanning multiple columns).

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