On Sun, Jul 18, 2010 at 1:39 PM, Leandro Hermida <[email protected] > wrote:
> On Sun, Jul 18, 2010 at 7:49 PM, Peter Rabbitson > <[email protected]<rabbit%[email protected]> > > wrote: > >> On Sun, Jul 18, 2010 at 02:40:47PM +0200, Leandro Hermida wrote: >> > very good points and makes a lot of sense. If I can ask a more general >> > question then, why do ORMs exist in the first place and why are they so >> > popular vs using a object persistence mechanism? There must be some >> serious >> > advantage to using them. >> > >> >> Because there yet does not exist a persistent object store, that can be >> asked to fetch "all objects which have related objects whose attribute X >> is Y", and which will do so by *transparrently* using native SQL methods >> (namely GROUP BY over a joined resultset). Matt Trout is working on the >> foundation of just such a "mapper", but this is a very very hard problem >> to get right, so progress is slow. >> > > I know this might sound sacrilegious, but established frameworks like > Hibernate have solved this problem and the code is freely available, I think > it would be easier to see how such complex ORM details are done there as a > starting point and then go from there other than starting from completely > scratch? > I'm confused, are you saying that Hibernate can be asked to fetch all objects which have related objects who attribute X is Y and it solves this problem by transparently using native SQL methods (like GROUP BY over a joined resultset)? Or are you saying that Hibernate can fetch all objects using some other method of query and retrieval? David -- "If only I could get rid of hunger by rubbing my belly" - Diogenes
_______________________________________________ List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class IRC: irc.perl.org#dbix-class SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ Searchable Archive: http://www.grokbase.com/group/[email protected]
