Thread: your thoughts on a crazy idea please
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
-----Original Message----- From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Andrew Chambers Sent: Thursday, March 31, 2005 4:46 PM To: postgres Subject: [GENERAL] your thoughts on a crazy idea please 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. ===================================================================>> If you use libpq then you can write any sort of interface to PostgreSQL that your heart might desire. <<=================================================================== 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
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