Re: Evolution of Date's "Abstract Machine" (via CM)

"Alfredo Novoa" <alfredo_novoa_at_hotmail.com> wrote in message news:1117884070.811958.164580_at_g47g2000cwa.googlegroups.com...
>>> Not exactly. The abstract machine, as I understand it (I don't have his
>>> source references), is the relational data model - not a specific data
>>> model, for a particular application. So while relational doesn't
>>> evolve, my database for my application does.
>
>>OK, thanks for this clarification. It is probably close to the mark.
>>Date goes on (in the above ref) to define two meanings for the
>>term "data model". The first and more fundamental meaning is given
>>in the above definition.
>
> [snip]
>
>>He would probably acknowledge that the data model in the
>>first sense (ie: the RM) only evolves though advance of
>>"relational theory", such as a new database language.
>
> Eric told you that the Relational Model does not evolve, and a new
> database language is not an advance in relational theory.

The Relational Model *will* evolve because at the moment it is a model only of the data (and its constraints, etc) whereas what is required to be modelled is both data and processes.

Everything evolves.

-- 
Pete Brown
IT Managers & Engineers
Falls Creek
Australia
www.mountainman.com.au/software