>As always thanks for bringing something extra to the table. We always think and answer questions is the scope of our own experience ( and knowledge ) and I'm really glad this question was asked and to see your answer. While I'm confident mine works in the scope i deal with, I have just learned a lot about a question I didn't know was a question <g> and will be watchful of *ass*uming my world is *the* world <g>
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>Now I have to go read a bunch of stuff I didn't know existed <s> You really know how to screw up my weekend.
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>I'd rather bring beer to the table. <s>
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>Working in this industry is much like being a doctor/surgeon (except we don't get paid quite as well). A person has to be reading almost constantly, to keep up with what's outside.
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> I'm fortunate in that I have hundreds of students who graduate and then email me back and tell me how they're using the technology in small-medium-large companies. Sometimes they recognize patterns I previously told them about, and sometimes they tell me about approaches being used that I've never heard of (and then MY weekend gets blown researching what they're talking about).
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>Now, on the original question, I am sure that many people have used zeros or nulls instead of an "unassigned" member/row, and the sky didn't fall. This industry is rarely an exact science. But there's a single magic word in the business application area....the magic word "by". Users (and execs) want to see data "by this", "by that", "by every possible combination". And so the more a database is built to support that, the happier everybody is.

One bias I have, and admit to, is for database knowledge as it applies to interactive CRUD applications. That is what I know. I have done enough reading to know there is a whole different world out there called OLAP, which is where you are coming from here. You have brought the point home. In a static database used for reporting, slicing and dicing, the rules of referential integrity do not apply. The data is fixed and the issue shifts to accessibility and performance.