Khussian,

I think we faced the same problem. (refer to today's thread "How to find duplication key")

It could have people create the first table without enforcng the constraints, and later they changed their mind and put constraints in it. In my case, I disabled the primary key (cascade) and copy that original table to another data source, then enabled the primary key in the original table, so it will not harm the original table, while I get the copy of it successfully.
Hope it helps.

[Edited by E-Quality on 08-26-2002 at 03:42 PM]