Rails中是否有find\u或create\u by\u接受哈希?

first_or_create 到ActiveRecord。它不仅具有所请求的功能,而且还适合其他ActiveRecord关系:

Task.where(attributes).first_or_create

在Rails 3.0和3.1中:

Task.where(attributes).first || Task.create(attributes)

Task.first(:conditions => attributes) || Task.create(attributes)

在旧版本中,您总是可以编写一个名为 find_or_create

class Task
  def self.find_or_create(attributes)
    # add one of the implementations above
  end
end

我还扩展了@wuputah的方法来接受散列数组,这在内部使用时非常有用 db/seeds.rb

class ActiveRecord::Base
  def self.find_or_create(attributes)
    if attributes.is_a?(Array)
      attributes.each do |attr|
        self.find_or_create(attr)
      end
    else
      self.first(:conditions => attributes) || self.create(attributes)
    end
  end
end


# Example
Country.find_or_create({:name => 'Aland Islands', :iso_code => 'AX'})

# take array of hashes
Country.find_or_create([
  {:name => 'Aland Islands', :iso_code => 'AX'},
  {:name => 'Albania', :iso_code => 'AL'},
  {:name => 'Algeria', :iso_code => 'DZ'}
])