What's the difference between data Validation and Verification?

Question

My recollection from a past employer is that they distinguished between the two as follows:

• Validation is the process of checking that the data is appropriate in a very basic sense; for example that data in a date field can be converted to a date, or that characters in a number field can be converted to a number of the appropriate type;
• Verification is the process of checking the typed data against some other 'business' rules that you impose on your interface - for example that the Date Of Birth field indicates an applicant within a certain age range.

These memories do not tie in with the Wikipedia article on the subject, nor a BBC BiteSize Revision article.

So what is the consensus: Do people care what methods and processes are called when I am checking Xml inputs for example?

What am I doing when I:

1. Check that a date field contains characters that are convertible to a C# DateTime;
2. Check that the DateTime is in an appropriate date range to be stored in SQL Server;
3. Check that the Date Of Birth indicates a customer over 18 but under 65?

Answer 1

Ok, so I'll take this as an open invitation to musing...

I think the difference is very much like compile-time vs. runtime errors. Just like the compiler is able to tell that two variables a,b are of type double, and thus the expression a/b is valid, it is only during runtime a DivideByZeroException may be raised if b turns out to be 0.

So to complete the analogy, one can validate that a string looks like a credit card number ('compile time'), but can only verify that it corresponds to a valid card only if one tries to charge the credit card ('runtime') with an amount

Duh. So I guess I understand it pretty much like you old company does.