Hi there,
I've been doing some work in ASP, so I can tell you what errors feel like from that client. It sounds like you're working in Dephi, VB, something like that, so this may not apply much....
Anyway, when running sql or stored procedures from ASP via ADO, constraint violations etc definitely generate errors, and these come back as error parameters in the ADO connection object. But at that point, it's up to the designer to decide what the client program should do with that error. You could do nothing, not notify the client, and he would be unaware that an error had occurred at all.
What I do is check the errors on the connection, and when I see some then I put out a custom 'error' html page, telling him something tragic occurred, and display some of the info provided by the server message (error #, error test, etc).
But like I said, in ASP I can just ignore the error if I wanted to (which is not normally a good idea)
Do you have that kind of control in your client, where you can check for errors and program some pre-determined action to take?
If this is totally useless comment to you, please ignore!
bperry