Re: two nasty schemata, union types and surrogate keys

Brian wrote:

> Databases don't record objects: they record facts [...].

Admirably close, but not quite cigar-worthy. Databases record *assertions* of fact. The assertsions may be sincere and truthful, or sincere but false, or deceitful and false. As I have said before, it is useful to think of the content of a database as being like the testimony in a court case.

My point being: you don't care, and we don't have to care (for the purpose of designing the database or the software that operates on it), about facts. All that matters is that we can make the inferences that we should be entitled to make from the assertions. Whether the inferences turn out to be factual or not is just not our business.

I can't bring myself to discuss the indentity issue. I am hopelessly bored with the idea that every particle and every concept has a barcode buried in it somewhere if we look hard enough. The problem of identity is always solved by the business process, and if it isn't, that's life's way of saying it doesn't need solving.

-- 
Roy