Topic 4 - Validation & Verification

Validation is the (computer) automatic checking of data entered into a computer system to ensure that it is sensible/reasonable/legal (BUT not valid/correct).

e.g.

• Presence check on certain (specified) field. Customer has to enter all the starred fields before the program will allow you onto the next screen (relevant field has to be named). To make sure that there is a number in the account number field

• Format Check - Ensures that the right pattern of characters have been entered i.e. 2 letters followed by 6 numbers for a stock code. On an account number to ensure that there is one block of 8 numbers e.g. 50183478

• Check Digit Checks that the account number is possible under the system by doing some maths on it. Using calculations on the account number to generate a new last number.

• Range check on date of birth / amount allowed to be transferred. Check that there are no silly dates entered such as 30th of February for date of birth or date of delivery.

• Data type – No letters entered into a number field for quantity of goods.

• Fixed value - (Dropdown List) List of choices for title such as Mr, Mrs, Ms, Dr, etc

• Length Check - Checking a field is less than to or equal to a certain length of characters e.g. 15 characters for a firstname. On account number to ensure that the correct number of characters have been entered.

Verification is the (human) checking that data has been copied accurately from one medium to another (entered correctly but data might not itself be correct). Verification is the use of checks to make sure data is consistent and has not been corrupted.

• Proof reading
  – being asked to check what you have entered is correct before being allowed to move on. (Read before you submit).
  - Reading over what you have entered to make sure it is correct, i.e. asking people to be sure before progressing.
  

• Double entry
  – having to re-input your account number, email address or the password.
  - Being asked to type in your password twice, to ensure no mistakes are made.