These tables has :
has_and_belong_to_many for relationship

Then, I have a fourth table that is related with persons_friends;
I don’t know how to do a relationship between the fourth table and persons_friends

Poli

@users = User.find :all, :conditions => “name like ‘k%’�
@users.each {|u| u.subscriptions.each{|s| s.mail(u.email,s.email_format)}}

you could even get rid of @users and have the .each hanging off of the find.

You COULD do sommat like….

@users = find … blah blah …
@users.collect{|u| u.subscriptions.collect{|s| [u, s]}}.each{|t| t[1].mail(t[0].email, t[1].email_format)}

But it would be a bad idea, as you would be building an in-memory array with as many rows as you have subscriptions whos subscribers name begins with ‘k’.

Cheers,

Simon

P.S. Apologies for the unformatted code. It was late and I didn’t notice the list of allowable tags below :)

You’re right. In my rather contrived example it would be better to use the following code:

@users = User.find :all, :conditions => "name like 'k%'"
@users.each do |u|
  u.newsletters.each do |n|
    n.mail(u.email,n.subscription.mail_format)
  end
end

I am using the through associations in several places in one of my projects to good effect. When I get some time, I’ll post another entry that’s based on some real-world usage.