I''ve been fiddling around a bit with the concept of adding
"inferred
join" capabilities to a gem I''ve been working on.
The general idea, to me, is one that feels so "Rails-like" (as in,
principle of least surprise) that I was kind of surprised it wasn''t
already in.
The goal: If you''re selecting Articles, but the selection criteria are
based on stuff associated to articles, I shouldn''t need to think about
what needs to be joined in advance if I don''t want to. I should be
able to do...
Article.where(
:title => ''Hello world'',
:comments => {
:body => ''First post!'',
:moderations => [
:value < 0
]
}
)
...and end up with something like this:
SELECT "articles".*
FROM "articles"
INNER JOIN "comments" "mw_infer_comments"
ON "mw_infer_comments"."article_id" =
"articles"."id"
INNER JOIN "moderations" "mw_infer_moderations"
ON "mw_infer_moderations"."comment_id" =
"mw_infer_comments"."id"
WHERE ("articles"."title" = ''Hello world'')
AND ("mw_infer_comments"."body" = ''First
post!'')
AND ("mw_infer_moderations"."value" < 0)"
I have this working, in rough form, at
http://github.com/ernie/meta_where/tree/inferred_joins
(the relevant code is in meta_where/lib/inferred_join_dependency.rb
and query_methods.rb). It''s a bit kludgy at the moment, but this is
only my first stab at it.
I''m just curious if:
a. Anyone on core would be interested in something like this. If not,
I''m happy to maintain it in MetaWhere, as well, provided....
b. Anyone has suggestions for an improved implementation.
JoinDependency, and the association code in general, is kind of a pain
to work around right now. I suspect that bypassing JoinDependency
altogether for an alternative implementation would yield performance
and readability improvements.
Thanks!
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I suppose you could override Relation#build_where
def build_where(*args)
if result = super
case args.first
when Hash
# Figure out table names from *args here and add them to
join_values or something
else
super
end
end
end
I''m not very sure about the feature itself though. There are times
when you may want to eager load the joined table.
On Wed, Apr 21, 2010 at 1:52 AM, Ernie Miller <ernie@metautonomo.us>
wrote:> I''ve been fiddling around a bit with the concept of adding
"inferred
> join" capabilities to a gem I''ve been working on.
>
> The general idea, to me, is one that feels so "Rails-like" (as
in,
> principle of least surprise) that I was kind of surprised it
wasn''t
> already in.
>
> The goal: If you''re selecting Articles, but the selection criteria
are
> based on stuff associated to articles, I shouldn''t need to think
about
> what needs to be joined in advance if I don''t want to. I should be
> able to do...
>
> Article.where(
> :title => ''Hello world'',
> :comments => {
> :body => ''First post!'',
> :moderations => [
> :value < 0
> ]
> }
> )
>
> ...and end up with something like this:
>
> SELECT "articles".*
> FROM "articles"
> INNER JOIN "comments" "mw_infer_comments"
> ON "mw_infer_comments"."article_id" =
"articles"."id"
> INNER JOIN "moderations" "mw_infer_moderations"
> ON "mw_infer_moderations"."comment_id" =
"mw_infer_comments"."id"
> WHERE ("articles"."title" = ''Hello
world'')
> AND ("mw_infer_comments"."body" = ''First
post!'')
> AND ("mw_infer_moderations"."value" < 0)"
>
> I have this working, in rough form, at
http://github.com/ernie/meta_where/tree/inferred_joins
> (the relevant code is in meta_where/lib/inferred_join_dependency.rb
> and query_methods.rb). It''s a bit kludgy at the moment, but this
is
> only my first stab at it.
>
> I''m just curious if:
>
> a. Anyone on core would be interested in something like this. If not,
> I''m happy to maintain it in MetaWhere, as well, provided....
> b. Anyone has suggestions for an improved implementation.
> JoinDependency, and the association code in general, is kind of a pain
> to work around right now. I suspect that bypassing JoinDependency
> altogether for an alternative implementation would yield performance
> and readability improvements.
>
> Thanks!
>
> --
> You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Core" group.
> To post to this group, send email to rubyonrails-core@googlegroups.com.
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>
>
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On Tue, Apr 20, 2010 at 22:42, Pratik <pratiknaik@gmail.com> wrote:> I suppose you could override Relation#build_where > > def build_where(*args) > if result = super > case args.first > when Hash > # Figure out table names from *args here and add them to > join_values or something > else > super > end > end > end > > I''m not very sure about the feature itself though. There are times > when you may want to eager load the joined table.Definitely looks like a cool idea for a plugin though. You should keep working on it. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Core" group. To post to this group, send email to rubyonrails-core@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-core+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-core?hl=en.
On Apr 20, 2010, at 9:42 PM, Pratik <pratiknaik@gmail.com> wrote:> I suppose you could override Relation#build_where > > def build_where(*args) > if result = super > case args.first > when Hash > # Figure out table names from *args here and add them to > join_values or something > else > super > end > end > end > > I''m not very sure about the feature itself though. There are times > when you may want to eager load the joined table. >Thanks for the feedback, Pratik. That''s actually where I plugged in to do it in the linked github repo, but I sort of piggybacked on joindependency a bit to do the heavy lifting.>-- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Core" group. To post to this group, send email to rubyonrails-core@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-core+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-core?hl=en.
Ernie Miller
2010-Apr-23 15:12 UTC
Possible bug in JoinDependency code, and another take on inferred joins.
On Apr 20, 9:50 pm, Norman Clarke <nor...@njclarke.com> wrote:> > Definitely looks like a cool idea for a plugin though. You should keep > working on it.I''ve got an alternate take on the concept up at http://github.com/ernie/meta_where/tree/autojoin now. I think I like this one better, and it seems to work OK with eager_load and includes now, too. Activated by adding autojoin into the method chain. See the gist at http://gist.github.com/376585 for results. There may still be some broken stuff or drawbacks, but I''m feeling pretty good about it in general. While working on this, I came upon what I believe is a bug in a relatively unused part of the JoinDependency/eager_loading code pertaining to find_with_associations, though I may be mistaken. I''ve put up a lighthouse ticket at https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/4463 if anyone cares to confirm. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Core" group. To post to this group, send email to rubyonrails-core@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-core+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-core?hl=en.
Ernie Miller
2010-Apr-26 19:46 UTC
Re: Possible bug in JoinDependency code, and another take on inferred joins.
On Apr 23, 11:12 am, Ernie Miller <er...@metautonomo.us> wrote:> While working on this, I came upon what I believe is a bug in a > relatively unused part of the JoinDependency/eager_loading code > pertaining to find_with_associations, though I may be mistaken. > > I''ve put up a lighthouse ticket athttps://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/4463 > if anyone cares to confirm.By way of update, the bug was confirmed and the patch is available at https://rails.lighthouseapp.com/projects/8994/tickets/4463. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Core" group. To post to this group, send email to rubyonrails-core@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-core+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-core?hl=en.