Validation and Verification : Format Check

Validation and Verification : Format Check

A format check is a validation check which ensures that entered data is in a particular format or pattern. The format that data must be in is specified using an input mask. The input mask is made up of special characters which indicate what characters may be typed where.

In a particular database the following special characters can be used to define an input mask :

0 - A number must be typed in this position.
9 - A number may be typed in this position or it may be left blank.
L - A letter must be typed in this position.
l - A letter may be typed in this position or it may be left blank.
A - A letter or number must be typed in this position.
a - A letter or number may be typed in this position or it may be left blank.

Here are some input masks that could be used to validate three letter codes, car registration numbers and postcodes.

Input Mask	Purpose	Valid Data	Invalid Data
LLL	Three Letter Code	ABC AND OLD	AB B2H ABCD
LL00LLL	Car Registration Number	AB01CDE DH53MAN	AB1CDE HELLO A823HFA
Ll90 0LL	Postcode	WA14 9JD M90 4SJ BL9 0HN	WAM4 9PM WA6 13H M12 9Q

GCSE ICT Companion 04 - (C) P Meakin 2004