I have a complex graph of ActiveRecord entities that I want to load with one big honkin'' join query to avoid ripple loading. It''s for a report. However :include doesn''t get me all the way there because I want to load parents of parents (or children of children). I don''t mind doing the SQL by hand but I''m not quite sure what to do to get the result set into my model objects. I don''t want to bypass my model objects because they have important calculation methods I need. I''d like to run a raw SQL query and then somehow plug the results into model objects. Sooo, what''s the best way to go about this? Thanks! Steve -- Posted via http://www.ruby-forum.com/.
Stephen Molitor wrote:> However :include doesn''t get me all the way there because I want to load > parents of parents (or children of children). I don''t mind doing the > SQL by hand but I''m not quite sure what to do to get the result set into > my model objects. I don''t want to bypass my model objects because they > have important calculation methods I need.You can load children of children with :include, eg Foo.find :all, :include =>[:{children=>[:children_of_children]}] -- Posted via http://www.ruby-forum.com/.
Frederick Cheung wrote:> You can load children of children with :include, eg > Foo.find :all, :include =>[:{children=>[:children_of_children]}]Awesome, thanks! I''m not sure if I understand the syntax. Are the curly braces necessary? Steve -- Posted via http://www.ruby-forum.com/.
Stephen Molitor wrote:> Frederick Cheung wrote: >> You can load children of children with :include, eg >> Foo.find :all, :include =>[:{children=>[:children_of_children]}] > > Awesome, thanks! I''m not sure if I understand the syntax. Are the > curly braces necessary? > > SteveSlight typo: should be Foo.find :all, :include =>[{:children=>[:children_of_children]}] IIRC you do need the braces generally, although you can probably omit for the example above. You do need them for stuff like Foo.find :all, :include =>[{:children=>[:children_of_children]}, :other_attribute] -- Posted via http://www.ruby-forum.com/.
Stephen Molitor
2006-Jul-03 15:41 UTC
[Rails] Combining :include and :joins (was Re: Eager loading...)
Thanks again. Sounds like I''ve got an ActiveRecord guru here. Related question: Can I join and include the same table? I want to filter based on a condition in the joined table, but I also want to eagerly load that table. Ideally I''d like to do that with just one join in the generated SQL. Can I refer to included tables (via :include) in my :conditions clause? Steve -- Posted via http://www.ruby-forum.com/.
Frederick Cheung
2006-Jul-03 16:04 UTC
[Rails] Combining :include and :joins (was Re: Eager loading...)
Stephen Molitor wrote:> Thanks again. Sounds like I''ve got an ActiveRecord guru here.You''re just to lucky to stumble onto one of the things I have worked out.> Related question: Can I join and include the same table? I want to > filter based on a condition in the joined table, but I also want to > eagerly load that table. Ideally I''d like to do that with just one join > in the generated SQL. Can I refer to included tables (via :include) in > my :conditions clause? > > SteveI''ve never tried :join and :include of the same table (which I suspect would be counter productive), however I have used the :included tables in the :conditions parameter without any problems. The only thing you need to be careful about is that you have to disambiguate all the column names (eg foos.bar = ''baz'' instead of bar = ''baz'') Fred -- Posted via http://www.ruby-forum.com/.
Stephen Molitor
2006-Jul-03 16:05 UTC
[Rails] Combining :include and :joins (was Re: Eager loading...)
Frederick Cheung wrote:> I''ve never tried :join and :include of the same table (which I suspect > would be counter productive), however I have used the :included tables > in the :conditions parameter without any problems. The only thing you > need to be careful about is that you have to disambiguate all the column > names (eg foos.bar = ''baz'' instead of bar = ''baz'')OK will do. Thanks again! Steve -- Posted via http://www.ruby-forum.com/.
Frederick Cheung wrote:> Stephen Molitor wrote: >> Frederick Cheung wrote: >>> You can load children of children with :include, eg >>> Foo.find :all, :include =>[:{children=>[:children_of_children]}] >> >> Awesome, thanks! I''m not sure if I understand the syntax. Are the >> curly braces necessary? >> >> Steve > > Slight typo: should be > Foo.find :all, :include =>[{:children=>[:children_of_children]}] > > IIRC you do need the braces generally, although you can probably omit > for the example above. You do need them for stuff like > Foo.find :all, :include =>[{:children=>[:children_of_children]}, > :other_attribute]Awesome +1 ! I was just about to post a question about exactly this issue, and here is the answer. Some days I just love the Internet :) Robert Jones -- Posted via http://www.ruby-forum.com/.
Frederick Cheung wrote:> Stephen Molitor wrote: >> Frederick Cheung wrote: >>> You can load children of children with :include, eg >>> Foo.find :all, :include =>[:{children=>[:children_of_children]}] >> >> Awesome, thanks! I''m not sure if I understand the syntax. Are the >> curly braces necessary? >> >> Steve > > Slight typo: should be > Foo.find :all, :include =>[{:children=>[:children_of_children]}] > > IIRC you do need the braces generally, although you can probably omit > for the example above. You do need them for stuff like > Foo.find :all, :include =>[{:children=>[:children_of_children]}, > :other_attribute]I''m getting a syntax error here - no doubt something stupid: @guidance_group=GuidanceGroup.find(@params[:guidance_group_id], \ :include=>[{:pupils=>[:setlinks], :pupil_sets, :guidance_group, \ :academic_year]}) RadRails is pointing to the comma after :pupil_sets Can anyone see the problem? Cheers, Robert Jones -- Posted via http://www.ruby-forum.com/.
I think you have an extra ] after :setlinks and an extra [ at the start. Try
this out.
@guidance_group=GuidanceGroup.find(@params[:guidance_group_id],
:include=>{:pupils=>[:setlinks, :pupil_sets, :guidance_group,
:academic_year]})
On 7/3/06, Robert Jones <jonesieboy@gmail.com>
wrote:>
> Frederick Cheung wrote:
> > Stephen Molitor wrote:
> >> Frederick Cheung wrote:
> >>> You can load children of children with :include, eg
> >>> Foo.find :all, :include
=>[:{children=>[:children_of_children]}]
> >>
> >> Awesome, thanks! I''m not sure if I understand the
syntax. Are the
> >> curly braces necessary?
> >>
> >> Steve
> >
> > Slight typo: should be
> > Foo.find :all, :include =>[{:children=>[:children_of_children]}]
> >
> > IIRC you do need the braces generally, although you can probably omit
> > for the example above. You do need them for stuff like
> > Foo.find :all, :include =>[{:children=>[:children_of_children]},
> > :other_attribute]
>
> I''m getting a syntax error here - no doubt something stupid:
>
> @guidance_group=GuidanceGroup.find(@params[:guidance_group_id], \
> :include=>[{:pupils=>[:setlinks], :pupil_sets, :guidance_group, \
> :academic_year]})
>
> RadRails is pointing to the comma after :pupil_sets
>
> Can anyone see the problem?
>
> Cheers,
>
> Robert Jones
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
--
Mark Van Holstyn
mvette13@gmail.com
http://lotswholetime.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
http://wrath.rubyonrails.org/pipermail/rails/attachments/20060703/8ac0b119/attachment-0001.html
> @guidance_group=GuidanceGroup.find(@params[:guidance_group_id], \ > :include=>[{:pupils=>[:setlinks], :pupil_sets, :guidance_group, \ > :academic_year]}) > > RadRails is pointing to the comma after :pupil_setsIt''s telling you that because it thinks you''re in a hash: it''s expecting a =>. You''re best placed to know what you actually mean, but i suspect you actually want :include => [{:pupils=>[:setlinks]}, :pupils_sets, :guidance_group, :academic_year] (assuming :setlinks is an attribute of each pupil and everything else is an attribute of GuidanceGroup) -- Posted via http://www.ruby-forum.com/.
Mark Van Holstyn
2006-Jul-03 17:58 UTC
[Rails] Combining :include and :joins (was Re: Eager loading...)
Using include on the same table works just fine. For one of my applications I have a table projects, which references itself because projects can have subprojects which can have more subprojects, etc... class Project < ActiveRecord::Base Project.find :all, :include => :child_projects On 7/3/06, Stephen Molitor <smolitor@erac.com> wrote:> > Frederick Cheung wrote: > > > I''ve never tried :join and :include of the same table (which I suspect > > would be counter productive), however I have used the :included tables > > in the :conditions parameter without any problems. The only thing you > > need to be careful about is that you have to disambiguate all the column > > names (eg foos.bar = ''baz'' instead of bar = ''baz'') > > OK will do. Thanks again! > > Steve > > -- > Posted via http://www.ruby-forum.com/. > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails >-- Mark Van Holstyn mvette13@gmail.com http://lotswholetime.com -------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060703/c03c257e/attachment.html
Mark Van Holstyn
2006-Jul-03 18:02 UTC
[Rails] Combining :include and :joins (was Re: Eager loading...)
Sorry, accidently hit send before I was done... class Project < ActiveRecord::Base belongs_to :parent_project, :class_name => ''Project'', :foreign_key => ''parent_project_id'' has_many :child_project, :class_name => ''Project'', :foreign_key => ''parent_project_id'' end Project.find :all, :include => :child_projects This works just fine and I am able to load any project, with all child projects in one sql query. -- Mark Van Holstyn mvette13@gmail.com http://lotswholetime.com -------------- next part -------------- An HTML attachment was scrubbed... URL: http://wrath.rubyonrails.org/pipermail/rails/attachments/20060703/3803698e/attachment.html
Frederick Cheung wrote:>> @guidance_group=GuidanceGroup.find(@params[:guidance_group_id], \ >> :include=>[{:pupils=>[:setlinks], :pupil_sets, :guidance_group, \ >> :academic_year]}) >> >> RadRails is pointing to the comma after :pupil_sets > > It''s telling you that because it thinks you''re in a hash: it''s expecting > a =>. > You''re best placed to know what you actually mean, but i suspect you > actually want > :include => [{:pupils=>[:setlinks]}, :pupils_sets, :guidance_group, > :academic_year] > (assuming :setlinks is an attribute of each pupil and everything else is > an attribute of GuidanceGroup)Cheers - that works. The reference to guidance_group as a child of guidance_group is as mysterious to me as to everyone else. Just a slip of the fingers :) BTW, the reason I want to eager load absolutely everything is that the report I am creating is going to be hived off to a BackgrounDrb worker. I want to get all the ActiveRecord work done in the background, so that the rendering is done as quickly as possible once the worker has done its job. Robert Jones -- Posted via http://www.ruby-forum.com/.