Question

现有协会

class Job < ActiveRecord::Base
  belongs_to :client
  belongs_to :contact
  belongs_to :location
  has_one :geofence, :through => :location
end

class Client < ActiveRecord::Base
  has_many :contacts
  has_many :locations
end

class Contact < ActiveRecord::Base
  belongs_to :client
end

class Location < ActiveRecord::Base
  belongs_to :client
  belongs_to :geofence
end

class Geofence < ActiveRecord::Base
  has_many :locations
end

在尝试寻找从各种表中搜索字段的工作时，我会做这样的事情

@jobs = Job.find(:all, :joins => [:client,:contact,:location,:geofence], :conditions => ['geofences.address like ?',"%#{params[:term]}%"])

产生以下错误

ActiveRecord::StatementInvalid (Mysql::Error: Unknown column 'geofences_jobs_join.location_id'

来自以下查询

SELECT `jobs`.* FROM `jobs`   INNER JOIN `clients` ON `clients`.id = `jobs`.client_id  INNER JOIN `contacts` ON `contacts`.id = `jobs`.contact_id  INNER JOIN `locations` ON `locations`.id = `jobs`.location_id  INNER JOIN `locations` geofences_jobs_join ON (`jobs`.`id` = `geofences_jobs_join`.`location_id`)  INNER JOIN `geofences` ON (`geofences`.`id` = `geofences_jobs_join`.`geofence_id`)  WHERE ...

有没有办法通过作业模型中的不同关联或查询的连接部分来解决此问题？

我可以使用find_by_sql获得我需要的东西，但如果可能的话我想避免这种情况。

Answer 1

我认为，为了使用has_one :through关联，您的Job模型应该声明has_one :location关联，而不是相反，请参阅this example。

也就是说，您可以尝试重新定义此关联并将location_id外键从jobs表移动到位置中的job_id，或者尝试此查询：

@jobs = Job.find(:all, :joins => [:client, :contact, { :location => :geofence }], :conditions => ['geofences.address like ?',"%#{params[:term]}%"])

在后一种情况下，您必须删除has_one :through。

has_one：through =＆gt; ：belongs_to产生错误的查询

1 个答案: