>Hi, Kev.
>
>>Following on from your example, one thing I've just been looking at is validation of entered values.
>>
>>My first reaction was that the middle-tier should check validity of passed values, because the UI doesn't need to know what data can be accepted.
>>
>>So if say, entering a product code, you accidently put a space in the middle, should the middle-tier be the tier to pick that up and return an error code?
>
>As usual, that depends. In many cases this can be handled in both sides.
>
>For example, your mid-tier can (indeed, it must) perform a final validation before commiting the transaction, to be sure that everything went ok. As I said, if you're just trying from the command window, you basically have no validation at all, but the BizObj should be smart enough to avoid processing wrong values.
>
>Beside that, checking values interactively all the time would mean a lot of traffic between tiers, so the basic validation could be done client-side, to avoid the user to enter bad values and report her about that at the very last moment.
>
>Indeed, this is the normal procedure. In a VFP client you can make wonderful realtime validation. In a web page (different fron-ent, same middle-tier), you are usually mucho more limited in what you can validate on the fly, and have to wait until the user clicks the submit button.
>
>Are you figuring the whole pattern?

Yep, thanks.

Kev