dynamic :conditions for activerecord associations?

rubyonrails-talk
1

Hello.

I'm facing the problem where I have something like this: class Person   has_many :things,            :conditions => "dynamic conditions depending of the object" end

So, the problem is that i would like to have a dynamic condition which depends upon the object. In my particular case, it is something like this:   has_many :things,            :conditions => {:country_code => 'country_code_string'}

So, let's say that the country_code_string might be 'UK', 'US' and so on. How can I make this kind of association? I tried lambda, like i could use in before_add, after_add and other callbacks, but then it seems that Proc object's string representation is used in WHERE clause. Is there even possible to have such thing or should i use something like: has_many :thingsUS,          :conditions => {:country_code => 'US'} has_many :thingsUK,          :conditions => {:country_code => 'UK'} ...

It doesn't feel much of an elegant solution to me. Better ideas how to solve this problem?

Jarmo

2

I haven't tried this, but you may want to give it a shot. You could set up a method on Person that scopes the association:

class Person   has_many :things   def things_for_country(code)     things.scoped(:conditions => { :country_code => code })   end end

And then calling it would look like (assume @person is a Person object):

@person.things_for_country('US')

This will certainly work for *finding* records; I'm not 100% sure what will happen with building/adding objects - it is likely to work, but you should definitely write some tests...

Hope this helps!

--Matt Jones

3

Hello.

Thank you for your suggestion.

I tried it and it worked for finding, but adding doesn't work unfortunately.

Jarmo

4

I suspected that adding with << wouldn't work; does using the build or create method work?

--Matt Jones