Rails 搜索查询关联模型

Question

In railscast #37 they show a simple search I am trying to implement. I have the following association:

class Owner < ActiveRecord::Base
    has_many :dogs
end

class Dog < ActiveRecord::Base
    belongs_to :owner
end

The Dog model has an attribute "name" and so does the owner. I need to be able to filter a list of dogs so that if you type "Fido" (dog) or "Bob" (owner) Fido will show up in the list. Here is how the search is currently set up:

model dog.rb:

def self.search(search)
    if search
      find(:all, :conditions => ['name LIKE ?', "%#{search}%"])
    else
      find(:all)
    end
end

this will return ONLY search terms matching the dog name (owner name is ignored)

I tried to change it to something like this:

  def self.search(search)
    if search
      find(:all, :conditions => ['name LIKE ? or owner.name LIKE ?', "%#{search}%", "%#{search}%"])
    else
      find(:all)
    end
  end

However is says there is no owner column. How do I change the search condition to be able to search both dog name and owner name?

Answer 1

Assuming that by following Rails convention you have tables named dogs for Dog model and owners for Owner model.

Update the search method as below:

  def self.search(search)
    if search
      joins(:owner).where('dogs.name LIKE ? or owners.name LIKE ?', "%#{search}%", "%#{search}%")
    else
      find(:all)
    end
  end

You need a join query between dogs and owners table in order to access owners.name field