Posted by --CELKO-- on 03/03/06 02:53
Read Dr. Codd or anyone else in RDBMS. Apparently none of the newbies
today do.
A key is **by definition** a subset of attributes of an entity. The
proprietary IDENTITY is an exposed physical locator derived from the
internal state of the hardware used to store that data. Or, to put it
another way, go to the real world that you are modeling and show me
where God put an IDENTITY number on the entities.
You have no way to validate or verify an IDENTITY because it is exposed
physical locator. It is a replacement for a SEQUENTIAL FILE record
number. It is totally non-relational.
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