Multiple choice technology databases

You need to enforce these two business rules: 1. No two rows of a table can have duplicate values in the specified column. 2. A column cannot contain null values. Which type of constraint ensure that both of the above rules are true ?

  1. Check

  2. Unique

  3. Not Null

  4. Primary Key

  5. Foreign Key
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A Primary Key constraint enforces both uniqueness (no duplicate values in a column or set of columns) and the not-null constraint (columns in a primary key cannot contain nulls). A Unique constraint allows nulls, Not Null does not enforce uniqueness, and Check and Foreign Key constraints enforce different rules.

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