Range Check
Ensures a value falls within an acceptable minimum and maximum range.
Type Check
Ensures data entered is the correct data type (e.g. integer, not text).
Length Check
Ensures input meets a required number of characters (minimum, maximum, or exact).
Presence Check
Ensures that a required field has not been left empty.
Format Check
Ensures data matches a specific pattern or structure (e.g. email contains @).