However I will not allow it to be said RDBMS do not support ISA relationships, when they are clearly supported and the relationship follows directly from normalization.

Wrong. That is completely and utterly wrong. RDBMSes support HAS-A relationships, in that a lineitem record HAS-A invoice record that it is on. Set theory (which RDBMSes are based on) is all about HAS-A relationships. The only IS-A relationship is the relationship between the specific record and the table it lives in. The person you are attempting to lay the smack-down is absolutely correct.

You might do well to rethink exactly what an IS-A relationship is vs. a HAS-A relationship and how normalization works with that.

------
We are the carpenters and bricklayers of the Information Age.

Then there are Damian modules.... *sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon. - flyingmoose

I shouldn't have to say this, but any code, unless otherwise stated, is untested

In reply to Re^5: OO concepts and relational databases by dragonchild
in thread OO concepts and relational databases by dragonchild

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