Surrogate keys, Sixth Normal Form and Anchor Modeling,
Date: Thu, 11 Apr 2019 15:33:16 -0700 (PDT)
Message-ID: <cb4bd97f-6b0d-4341-9deb-74d90c444c83_at_googlegroups.com>
The authors of Anchor Modeling "using" 6NF and refer to surrogate key. This means that the authors of "anchor modeling" are based on the surrogate key prescribed by Edgar Codd and the 6NF defined by C. Date and H. Darwen. But it must be said, surrogate key and 6NF are scientific failures. Why we should say that 6NF and surrogate key are science failures? I will state only three reasons:
1.
In fact, here matter is about atomic structures. These are the following
fundamental questions: From what are thoughts, concepts, propositions,
predicates and objects are constructed? From which atoms they are
constructed?
2.
Another reason is that there are thousands of people here, maybe millions,
who learn and spend time on reading and learning the wrong "theories".
3.
In my opinion, in the world of scientific journals and the publishing of
scientific papers, not-scientific means have begun to be applied, as in the
case of "anchor modeling".
Examples
Codd uses the "surrogate key" as the main part of his paper “Extending the
database relational model to capture more meaning“. Codd wrote in section 4
„ Database users may cause the system to generate or delete surrogate, but
they have no control over its value, nor is its value ever displayed to
them.“
Why has Codd introduced this limitation for users? The reason is as follows:
If the user can see the surrogates then the user can change these
surrogates. And that means chaos in DB. It is clear to everyone that it
makes no sense to construct atomic structures with a complex key.
C.J.Date wrote the definition of Candidate Key:
Candidate key for R is a subset of the set of attributes of R, say K, such that:
1. No two distinct tuples have same value for K. 2. No proper subset of K has uniqueness property.
Obviously in this theory about the candidate key does not fit Codd's surrogate key.
Date & Darwen in their book "Temporal Data and the Relational Model" used one database as a working example for the whole book. In this database all the keys are simple.
However, if the keys are complex, then their solution is not "atomic". The general case is a complex key. The theory must be made for the general case. Date & Darwen did a special case.
Most importantly, Date & Darwen did not give any procedure that brings any relation to atomic structures.
The authors of Anchor Modeling put the "Sixth Normal Form" in the title of their paper: „Anchor Modeling An Agile Modeling Technique using the Sixth Normal Form for Structural and Temporally Evolving Data“.
Vladimir Odrljin Received on Fri Apr 12 2019 - 00:33:16 CEST