>>>What is the most efficient way of handling this?
>>>Assuming I have a compound PKEY or CANDIDATE
>>>should I do a SEEK before modifying a one of
>>>the components or is it more efficient to trap
>>>for the error?
>>>
>>>   ...kt
>>
>>I usually do both. Not sure, it's the right approach (I had several discussions here about this problem), but this is how it works in our system (single tier):
>>I have a special textbox class, which checks for uniqueness of the entered value (if it's not unique, User can correct it immediatelly) and our form also has some mechanism to deal with errors on the save stage.
>>
>
>Hi Nadya,
>
>My situation is a bit different. I have a merge
>application where I need to merge 10K to 100K
>records at a time. I'm trying to find out if
>anyone has done any benchmarks that indicate
>which is actually the most efficient method of
>checking for duplicates.
>
>   ...kt

See FAQ about finding orphans. Could you show some code fragment? Assuming, you have one master table and you have to append from different sources, but only if you don't have already entered same values in the master table you can use scan with either keymatch (if appropriate) or indexseek conditon. It would be quite fast.