Re: some information about anchor modeling
Date: Mon, 5 Nov 2012 21:44:14 +0000
Message-ID: <slrnk9gcpe.8dj.eric_at_teckel.deptj.eu>
On 2012-11-04, vldm10 <vldm10_at_yahoo.com> wrote:
...
>> Google gives a Safari book preview of a few lines, below. (I have the
>> book, this enough to give you an idea of his usage, introduced here.) See
>> http://en.wikipedia.org/wiki/Relational_Model/Tasmania re kernel entities
>> of RM/T.
> Let me comment only few basic things from this web site. In the section
> "Summary of RM/T", the following basic concepts are defined:
(re-ordered)
> (ii) Definition
> A nonentity is some thing that is not an entity?
>
> my comment: Note that ?entity? and ?thing? are synonyms.
>
> (i) Definition
> Surrogates. A surrogate is a unique value assigned to each entity.
>
> my comment: The entity is the real world object and it is not possible
> to assign value to the real world object.
> (iii) Definition
> The RM/T addresses atomic semantics by?
>
> my Comment: With the most carefully observing the RM / T, one could not
> find a single atom of the semantics, because in the RM/T, section 4,
> E. Codd wrote: "Database users may cause the system to generate or delete
> a surrogate, but they have no control over its value, nor is its value
> ever displayed to them.?
Eric
-- ms fnd in a lbryReceived on Mon Nov 05 2012 - 22:44:14 CET