(assume for now person:emp is N:1)

..it could (by defining the PK as person_id) , but it still creates an extra unnecessary table

..and the second point about absence of a...

..yes I thought about that as I wrote it - however there are many places where you don't want to create a link table as the relationship is genuinely 1:N...

Hi

I'm not sure I agree exactly with your rule 1- or at least how you've used the idea of "unknown" to say what NULL is.

Consider when using foreign keys..

table EMPLOYER

id

name...

It's most noticeable in the contract market, where unless you're available yesterday, you won't get an interview.

This to me seems to encourage hiring the worst candidates, as they're most...

Oracle has "Connect by prior"

select * from person connect by prior id=supervisor_id

.. it makes traversing hierarchies trivial.

I was hoping it would appear in SS2005... 

..a bit of everything, as I'm a one man band!

Interesting about the Production DBA doing a bit of development..

I worked for a big Credit Card company, and they had a...