> Is there any way to enforce uniqueness of all non-nulls in a nullable > column?
> The "business requirement" would be "this kind of thing has an optional > attribute, that, if it exists, is unique". For example, a company may or > may not exist in the Byro van Dijk company database, but if it does > exist it will have a unique BvD id. I'd like to enforce this uniqueness. I'm sure I don't understand the question properly, because a Firebid UNIQUE constraint on a null-able column doesn't take NULLs into account, as long as it isn't a compound UNIQUE constraint made up from > 1 columns. -- With regards, Thomas Steinmaurer (^TS^) Firebird Technology Evangelist http://www.upscene.com/ Do you care about the future of Firebird? Join the Firebird Foundation: http://www.firebirdsql.org/en/firebird-foundation/
