Dear Juston, Yes, the tutorial does explain it, after all and now I understand. Sorry, I missed it when looking before.
cheers, James. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Justin Ellison Sent: 31 January 2008 14:12 To: Rose::DB::Object list Subject: Re: [RDBO] redundant rows from queries with multiple one tomanyrelationships I think you're looking for this: http://search.cpan.org/~jsiracusa/Rose-DB-Object-0.7662/lib/Rose/DB/Object/M anager.pm#with_objects The message pertains to the JOIN's being created. You won't get duplicate rows, but you'll get duplicate data within the related rows. If you're okay with it, set multi_many_ok: http://search.cpan.org/~jsiracusa/Rose-DB-Object-0.7662/lib/Rose/DB/Object/M anager.pm#multi_many_ok The tutorial gives an example using "real" data: http://search.cpan.org/~jsiracusa/Rose-DB-Object-0.7662/lib/Rose/DB/Object/T utorial.pod#Auto-joins_and_other_Manager_features Basically, RDBO is issuing a disclaimer saying - "this SQL may be inefficient and slaughter my database with load, but I know what I'm doing and want to do it anyways" ;-) Justin > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of James Masters > Sent: Thursday, January 31, 2008 6:39 AM > To: Rose::DB::Object list (E-mail) > Subject: [RDBO] redundant rows from queries with multiple one > to manyrelationships > > > Dear Rosers, > > I have never fully understood the implications of this message: > > WARNING: Fetching sub-objects via more than one "one to many" > relationship > in a single query may produce many redundant rows, and the > query may be slow > > I have avoided doing such queries until now but now I have > reached that > point. I'm not fussed about the "slow" part of this - it's > the redundant > rows I want to avoid - doesn't this amount to an "incorrect result"? > > I've looked through the documentation and the discussions but > cannot find > anything comprehensively explaining the implications. I'm > sure I won't be > the only person who would appreciate a short piece with: > > The theory > A tiny example showing what can happen. > An explanation of when redundant rows do happen and > conversely when it's OK > to not worry (and use the multi_ok switch) > A way to use multiple one-to-many relationships without getting the > redundant rows. > > I don't want to waste anyone's time and possibly a piece outside Rose > documentation exists. Is there anything out there that will assist? > > thanks, > > James. > > > -------------------------------------------------------------- > ----------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Rose-db-object mailing list > Rose-db-object@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/rose-db-object > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Rose-db-object mailing list Rose-db-object@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rose-db-object
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