Rails3: Arel finder discovery!

rubyonrails-talk
1

Rail3 Arel finders are just great, but you can't find a lot of example on how powerful they really are.

I made a discovery, just experimenting with some chaining.

List say you have   Foo has may Bars

  @foo = Foo.find(1)

  @bar = @foo.bars

That would give you all the bars related to foo(1)

But you can also do:

  @bar = @foo.bars.order(:name).where(:elem => "something")

I guess it is like scopes, just not defined in the model.

I don't know if that was possible in rails2 (e.g., @bar @foo.bars.find(:conditions => "xxx"))

Not sure I have a use for it, but it was interesting that you can filter a nested has_many relationship.

Steve Alex

2

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I don't know if that was possible in rails2 (e.g., @bar @foo.bars.find(:conditions => "xxx"))

Not sure I have a use for it, but it was interesting that you can filter a nested has_many relationship.

I guess it was a learning experience for me. I don't think I every saw an example where you can filter a nested relation. Tried it in rails 2.3.8 and it worked - so it was not a discovery - except for me.

3

Also note that you can chain "magic finders" off the association as well; so

@foo.bars.find_by_name('xyzzy')

will work.

--Matt Jones