A quick correction on Colin's suggestion:
On Mon, Jul 13, 2015 at 2:44 AM, Colin Law <clan...@gmail.com> wrote:
> On 13 July 2015 at 01:10, j...@via.net <j...@via.net> wrote:
> > class Asset < ActiveRecord::Base
> > belongs_to :site
> >
> > # class variable :name
> >
> > end
> >
> > class Site < ActiveRecord::Base
> > has_many :assets
> >
> > # class var x, y, z
> >
> > end
> >
> > Is there a dynamic finder that will traverse the inner join:
> >
> > e.g. Site.find_by_asset_name("xyzzy")
>
> Asset.where( name: 'xyzzy').site
>
Asset.find_by(name: 'xyzzy').site
Because .where returns a collection, .find_by returns the first one found.
Asset.where(name: 'xyzzy').first = Asset.find_by(name: 'xyzzy')
(I make this same mistake a lot for some reason.)
> >
> > Can I get a list of sites where asset.name == "BAZ"
>
> Site.joins(:assets).where(assets: {name: "BAZ"})
>
> >
> > Can this be done in AR or do I have to resort to SQL?
>
> As you can see it can be done in AR. It is very rare to have to
> resort to SQL in Rails. If you do it often means you have not
> specified the associations correctly.
>
> Have a look at the rails guide on ActiveRecord Querying, and the other
> guides. In fact I suggest you start by working right through a good
> tutorial such as railstutorial.org, which is free to use online. That
> will show you the basics of Rails.
>
> Colin
>
> >
> > Thanks,
> >
> > Joe
> >
>
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