Hi, I''d like to ask something. I have messages and I have countries. I do searches of messages by country. So a country has_many messages and message belongs_to country. I have defined a country_id on the messages country. Is there a quick way to find how many messages belong to a country without going through the messages find? I thought of adding a counter to the country table and increase/decrease when a message for that country is handled. Is this the right approach? Thanks. -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
if you have that defined the Rails way with has_many, then: @country.messages.size would give you that number. You can enhance speed for that, by using has_many :messages, :counter_cache => true in countries model. This would require a column messages_count in countries --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Also, @country.messages.count will do an SQL COUNT query and return it. Thorsten''s suggestion is quicker of course since you''re only performing one query. ----- Ryan Bigg Freelancer http://frozenplague.net On 18/12/2008, at 12:56 AM, Thorsten Müller wrote:> > if you have that defined the Rails way with has_many, > then: > > @country.messages.size > > would give you that number. > > You can enhance speed for that, by using > > has_many :messages, :counter_cache => true > > in countries model. > This would require a column messages_count in countries > >--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Thanks a lot guys! -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---