As an academic exercise it would be interesting to try and create the
*next* RDBMS query language. In a production environment I do think the
idea is crazy.
I've got a little experience with this. Interbase used to support a more
procedural query language called GDML (along with SQL). I used it in a
production system. I had a reason, which was that it supported
multi-threading (like SET CONNECTION does in more recent SQL.) In
retrospect, it was a lousy decision.
First off, it wasn't all that popular, and Borland dropped support for it.
So much for maintenance. I was one of very few people who bothered to
learn it. Great job security, if you want to maintain a legacy system as a
job your locked into. Trained programmers, evolving capability, and a
helpful user community was nonexistent. You got a problem? You're on your
own.
Rick
pgsql-general-owner@postgresql.org wrote on 03/31/2005 07:46:02 PM:
> I came across an old RDBM called Business System 12
> (http://www.mcjones.org/System_R/bs12.html) a few days ago. It seemed
> to have a much simpler method of specifying queries - more similar in
> style to relation algebra than SQL. For example, some example code
> might look like this.
>
> view = join(rel_1, rel_2) --assertains join criteria
> based on primary keys
> filtered_view = select(condition_list, view)
> result = project(attribute_list, filtered_view)
>
> Ignoring for a minute that SQL is the accepted method of talking to
> databases, and also acknowledging that SQL may be more expressive than
> relational algebra, I wondered if it would be possible to extend
> Postgresql to allow non-sql interfaces to simple database services.
>
> I suppose it would be possible to convert statements like those above
> into their SQL equivalent before passing them to an existing driver, but
> from reading the docs, it seems that dbmses usually do these types of
> operations once they have parsed the SQL anyway.
>
> I'd be interested to hear your thoughts on the subject whatever they
> are. Critical comments are particularly welcome (they might be quite
> useful for getting this stupid idea out of my head ;-)).
>
> Regards,
> Andy
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings
