通过has_many通过的多个数据库连接
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25-10-2019 - |
题
如何通过使用多个数据库连接来制作has_many?
我有一个名为“主”的数据库,该数据库包含位置信息。从一个单独的应用程序更新。用户可以访问许多位置,但是所有其他模型都位于另一个名为“预算”的数据库中。这是设置模型的方式。
# place.rb
class Place < ActiveRecord::Base
belongs_to :user
belongs_to :location
end
# user.rb
class User < ActiveRecord::Base
has_many :locations, :through => :places
has_many :places
end
# location.rb
class Location < ActiveRecord::Base
establish_connection "master"
has_many :places
has_many :users, :through => :places
end
当我通过IRB运行命令时,我会得到以下内容
> Location.first.places.create(:user_id => 1)
> #<Place id: 1, user_id: 1, location_id: 1, created_at: "2011-11-28 20:58:43", updated_at: "2011-11-28 20:58:43">
> Location.first.places
> [#<Place id: 1, user_id: 1, location_id: 1, created_at: "2011-11-28 20:58:43", updated_at: "2011-11-28 20:58:43">]
> Location.first.users
> [#<User id: 1, username: "toby", role: "guest", created_at: "2011-11-28 17:45:40", updated_at: "2011-11-28 17:45:40">
> User.first.locations
> Mysql2::Error: Table 'master.places' doesn't exist: SELECT `locations`.* FROM `locations` INNER JOIN `places` ON `locations`.`id` = `places`.`location_id` WHERE `places`.`user_id` = 1 ActiveRecord::StatementInvalid: Mysql2::Error: Table 'master.places' doesn't exist: SELECT `locations`.* FROM `locations` INNER JOIN `places` ON `locations`.`id` = `places`.`location_id` WHERE `places`.`user_id` = 1
我尝试添加当前的Rails Env以尝试尝试并覆盖位置的默认数据库,例如:#place.rb class place <activerecord :: base stable_connection rails.env anders_to anders_to:user allat anders_to:位置端
#database.yml
master:
adapter: mysql2
encoding: utf8
reconnect: false
database: master
pool: 5
username: root
password:
socket: /var/run/mysqld/mysqld.sock
development:
adapter: mysql2
encoding: utf8
reconnect: false
database: budget_development
pool: 5
username: root
password:
socket: /var/run/mysqld/mysqld.sock
那无济于事。有任何想法吗?
解决方案
一个朋友为我回答了这一点,我认为这可能对其他人有用。
class Location < ActiveRecord::Base
#establish_connection "master"
def self.table_name() "master.locations" end
has_many :places
has_many :users, :through => :places
end
其他提示
答案对我有用,但是我在关系表中使用此版本:
self.table_name = "master.locations"
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