Re: Database design, Keys and some other things
Date: 29 Sep 2005 14:33:40 -0700
Message-ID: <1128029620.610189.274300_at_f14g2000cwb.googlegroups.com>
Proposition:
I am putting forward for discussion that Codd's Information Principle
(based on an Liebniz/essentialist viewpoint that an entity is defined
by its attributes, and is nothing more and nothing less than the
aggregate of them, [Celko - D&DB]) is not a complete model of the
nature of information. Rather I am proposing that there is no single
attribute of an entity that can be gauranteed to act as a permenant
immutable reference for it (nominalism - there are no universals), and
so an external one to represent our concept of an entity be provided.
Difficulties arising from the IP:
Primary Key non-mutability - often necessary to employ internal
surrogates that require management [Codd - RM/T paper].
Lack of Internal Referencing checks - often necessary to explicitly use
cascade mechanisms to prevent dangling references, orphan records.
Possible Solution:
provide any encoded proposition with an automated reference that
guarantees primary key mutability, but is externalised from the data,
which then remains a pure encoding of the representation of real-world
attributes (essentially the partial map that is the tuple becomes a
datatype) [W, Kent - D&R]. Joins may be pivoted on this reference, and
integrity is continually maintained by the DBMS between these
references to prevent orphan tuples.
Now I'm afraid, I have no more than that to offer at the moment. And obviously its all up for assassination, and thats no problem, shoot. That's why i'm posting - to get your educated opinions. Just don't tell me this sort of discussion isn't valid here (where else?), that I don't roll my sleeves up and do real work or that the questioning the philosophy of axioms is for high school. Received on Thu Sep 29 2005 - 23:33:40 CEST