RE: the idea of unique primary keys to be a solution that hasoutl ived its usefulness?

<snip>
Personally, I like the use of compound keys, but it's one of those YMMV
issues.  I think that most shops fail to use "Unique" keyword in DDS,
because they don't like trapping for I/O errors. 
<endsnip>

They should embrace this, though.  Because having ambiguity is a big pain. 
 Like the duplicate item number issue I've had.

In the past, errors were often assumed to be one issue.  For example if a 
write failed we may have assumed that it was because of a duplicate key. 
When it could have been any number of factors:
File was full.
The referential integrity pointed to a child that was missing, (like 
adding a order record when the customer number was not on file).
Trigger program objected to it and issued an escape message.


Rob Berendt
-- 
"They that can give up essential liberty to obtain a little temporary 
safety deserve neither liberty nor safety." 
Benjamin Franklin