Re: Copy From & Insert UNLESS

James,

Are you sure that a new type of constraint is the way to go for this? 
It doesn't solve our issues in the data warehousing space.  The spec we 
started with for "Error-tolerant COPY" is:

1) It must be able to handle parsing errors (i.e. bad char set);
2) It must be able to handle constraint violations;
3) It must output all row errors to a log or "errors" table which makes 
it possible to determine which input row failed and why;
4) It must not slow significantly (like, not more than 15%) the speed of 
bulk loading.

On that basis, Alon started working on a low-level error trapper for 
COPY.   It seems like your idea, which would involve a second constraint 
check, would achieve neigher #1 nor #4.

--Josh Berkus