Ruby/Rails - Nested blocks without hitting the DB everytime?

Question

Not exactly sure how to look this up, but I'm not finding the solution anywhere. I want to assign an array of users an array of websites. Like so:

users = User.all
sites = Site.all

users.each do |user|
  sites.each do |site|
     user.websites << site
  end
end

Obviously, this does not work because I'm missing something about block scope. However, this works:

users.each do |user|
  Site.all.each do |site|
    user.websites << site
  end
end

But I'm trying to eliminate the extra calls to the DB (Site.all.each ...) and learn something about Ruby in the process. Any help is greatly appreciated.

Answer 1

I'm not sure why the first attempt wouldn't work, but I also don't really understand why you'd append each site separately. Wouldn't this work?

users = User.all
sites = Site.all

users.each do |user|
    user.websites.concat(sites)
end

ruby-doc link to concat

If they're actually hashes (although you say they're arrays), the method you're looking for is merge

Answer 2

If your User model is in a has many relationship with Websites (classname Sites), then you can just do

users = User.all
sites = Site.all

users.each do |user|
  user.websites = sites
end

Edit: For Harpastum:

If user.websites contains items not in Site.all that you don't want over written the following works.

users = User.all
sites = Site.all

users.each do |user|
  user.websites << sites
end