Multiple choice technology databases

What is true about CHECK constraint? Choose all that apply

  1. Must evaluate to BOOLEAN expression

  2. Not necessarily evaluates to BOOLEAN expression

  3. Requires that a column (or combination of columns) satisfy a condition for every row in the table excluding nulls.

  4. Columns which, are part of CHECK constraint, may accept NULL values

  5. Columns which, are part of CHECK constraint, can NOT accept NULL values
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Explanation

CHECK constraints must evaluate to a BOOLEAN expression (true/false), apply to every row excluding nulls (nulls don't trigger CHECK constraint violations), and columns in CHECK constraints can accept NULLs unless explicitly restricted by NOT NULL. The constraint only fails when a non-null value violates the condition.

Keep practicing — related questions