APEX

Hi

Firstly apologies for the slightly vague nature of the post, but I'm looking for some advice on best practice.

We are currently system testing our Apex application and we are getting some intermittent collection violations, the most frequent of which is ORA-00001: unique constraint (FLOWS_030000.WWV_FLOWS_COLLECTION_UK) violated

Having sat with our test team I believe these may be occuring when they are inadvertently double clicking on links, although i cannot be a hundred percent sure due to the speed they are working at! As an aside the problem doesnt appear to occur when people work "slower" or avoid double clicking - this leads me to suspect there may be some kind of internal race condition going on here

Whilst I understand that 2 clicks will result in 2 submissions and the constraint violation is responding to this scenario:
1) Double clicking on a lin is typical user behaviour - especially if the system isnt going as fast as they want
2) The default Apex response is to replace the page with a white Apex page with a red cross and an error message in the top left hand corner. This is highly concerning to a user as to them their application has "crashed" (although the back button does recover the situation)

My question is twofold
1) How do we track which collection is causing the error - at the moment we cant determine if its one of "our" collections or an Apex one (we've tried setting SQLTrace and using OEM but we didnt get anything helpful, however we may be missing a point)
2) How do we provide custom error handling so that when a bug or unexpected scenario occurs whilst the Apex page is processing we can divert the user to a more appropriate page


Many thanks for your help

Chris