I still think one shouldn't allow NULL values in unique constraints
unless it's the _only_ value (any value is unique if there are no other
values to compare with, after all), but I can't compare myself to
C.Date, Darwen or Tom Lane... I'm not a database deity :P
You can not declare a unique value on nothing... thus the reasoning :)
I suspect they have some pretty good reasons to treat NULL values in a
UNIQUE constraint as different even from other NULL values. It sure
makes me curious though ;)
Regards,
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