Re: Nested joins and ODBC

Jim,

Would you please explain to me how a union could replace a join? Unions are used to merge compatible rows resulting from subqueries into a single resultset. Joins are used to merge columns from different (related) tables into the rows of a resultset. They correspond to complementary operations from relational algebra. Neither of them can be replaced by the other.

Silvio

"Jim Kennedy" <kennedy-family_at_attbi.com> wrote in message news:IFgs8.236449$702.41206_at_sccrnsc02...
> Actually, why don't you use unions? Even more database neutral than the
> inner join syntax. If you have been developing since Oracle 6 then I
think
> that would be the first thing to try.
> Jim
> "Silvio Bierman" <sbierman_at_idfix.nl> wrote in message
> news:a8ror8$lcp$1_at_news1.xs4all.nl...
> > Daniel,
> >
> > Thanks for responding to my post.
> >
> > I would like to set the record straight: I have been developing Unix
based
> > Oracle applications (mainly server apps for voice-response environments,
> > some C/S desktop apps) since Oracle 6 and have years of experience as
both
> > application developer and database admin. I have a thorough
understanding
> > about the fundamental differences between Oracle and SQL-Server.
> Therefore,
> > I am not expecting Oracle to mimic SQL-Server behaviour.
> >
> > However, if Oracle distributes an ODBC-driver it automatically takes on
> the
> > burden of conforming to some of the mainstream behaviour most
ODBC-enabled
> > database platforms display. One particularly important area is that of
> > adhering to as much as possible of the ODBC SQL-grammar for SELECT,
INSERT
> > and UPDATE statements. If I am to develop a multi-backend app using ODBC
> > proprietary join operators simply aren't an option, be they Oracles (+)
or
> > SQL-Servers (*). The only way to overcome these differences is to rely
on
> > the ability of the ODBC-driver to interpret the ODBC join syntax and
> convert
> > to the proper backend-syntax.
> >
> > Therefore, my question is not so much about the Oracle database server
as
> it
> > is about the Oracle ODBC driver. If it is not able to do nested
ODBC-style
> > joins I think it is useless, despite the undisputed excellence of the
> > backend!
> >
> > Silvio Bierman
> >
> > "damorgan" <damorgan_at_exesolutions.com> wrote in message
> > news:3CAE3CFD.BEA87090_at_exesolutions.com...
> > > No you don't. What you need to do is get an Oracle book, open it, and
> read
> > > it.
> > >
> > > I work in Redmond, WA. Many of my friends work for Microsoft. But I
have
> > to
> > > confess I am getting sick and tired of the MS mentality which is that
> > > whatever way I did it in a Microsoft product is the way it works and
> > anything
> > > else is the work of a medieval demon or worse. Get over it. Quickly!
> > >
> > > If you are going to work in Oracle the first thing you need to learn
is
> > that
> > > it is not a Microsoft product. It does not work like a Microsoft
> product.
> > It
> > > is not supposed to work like a Microsoft product. And if Larry doesn't
> > lose
> > > his mind it never will. The syntax is different, the architecture is
> > > different, transactions are different, data integrity is different,
> > locking
> > > is different, and the very basis of the system is multiversioning
which
> > SQL
> > > Server doesn't have.
> > >
> > > So unless you have some over-riding desire to make a huge ugly mess
and
> > then
> > > blame it on Oracle get a book and read it. The problems with Oracle
will
> > not
> > > be the software. If you make an insecure, unscalable, lousy performing
> > home
> > > to corrupt data put the blame squarely where it belongs ... on
yourself.
> > >
> > > Back to your question: Can it be done? Of course. But only by people
who
> > > learn how!
> > >
> > > Daniel Morgan
> > >
> > >
> > >
> > > Silvio Bierman wrote:
> > >
> > > > Hello,
> > > >
> > > > I am porting a SQLServer app to Oracle 8 (using Oracle ODBC-driver)
> and
> > I
> > > > have stumbled onto a problem.
> > > >
> > > > I need to join three tables together using the join syntax:
> > > >
> > > > select * from a left outer join b on a.x=b.y left outer join c on
> > b.i=c.j
> > > >
> > > > When I join only two tables I can use
> > > >
> > > > select * from {oj a left outer join b on a.x=b.y}
> > > >
> > > > but this does not work when joining more than two tables.
> > > >
> > > > Can this be done?
> > > >
> > > > Because the app needs to run on SQLServer also I can not use the
> Oracle
> > > > outer join syntax!
> > > >
> > > > Regards,
> > > >
> > > > Silvio Bierman
> > >
> >
> >

>
> Received on Mon Apr 08 2002 - 09:01:01 CDT