Re: Data validation, mapping, and error handling

[Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx>]

Peter Dow (ML) wrote:
> I think you're 
> losing sight of the user here.
Not a chance.  Everything I'm talking about is predicated on creating a 
productive experience for the end user.

> With the 5250 interface, how the user 
> sees a VALUES or other validation error is probably going to be a lot 
> different than how a business rule validation error is presented.  I'd 
> say that's a pro for Aaron's philosophy of putting all the edits in one 
> place.
>   
Not sure I understand this statement.  You quote me below where I 
specifically separate data entry edits, reasonability checks and 
business rules.  My point is that the simpler checks (field required, 
for example) can be implemented outside of business logic and more 
specifically in the client code; in rich client applications this allows 
the edit checks to be made without round trips to the server.

My problem with the "all in one place" theory is that all edits, even 
smiple checks, should be re-implemented in the business logic itself.  
Thus, if you want your edits in one place and one place only, they all 
have to be in the server.  My point is that you can save the USER time 
if you put some of the checks in the client.

> But I can also see Joe's argument for having EGL do most of the work 
> (I'm a programmer too :-) ).  How does EGL present the validation errors 
> to the user?  Is it decent enough that you would have all your business 
> rule validation present the error the same way so the user has a better 
> experience?
>   
Presenting errors in EGL is simple: you place a tag where you want the 
error text to display.  Typically that would be in a cell in a table.  
To implement your own custom validation, you'd create an message 
variable and put that in the same cell.  That way, the cell would 
display either the automatic validation error or the error from the server.

Joe