[英]Rails association skip update associated object
class City<ActiveRecord::Base
has_one :template, class_name:'TmplLocation'
after_initialize :_init
private
def _init
self.template = TmplLocation.find(18) if !self.template
end
end
這就是控制台中發生的情況:
>Loc.first.template
City Load (29.8ms) SELECT `locations`.* FROM `locations` WHERE `locations`.`type` IN ('City') LIMIT 1
TmplLocation Load (0.2ms) SELECT `locations`.* FROM `locations` WHERE `locations`.`type` IN ('TmplLocation') AND `locations`.`location_id` = 23 LIMIT 1
TmplLocation Load (34.8ms) SELECT `locations`.* FROM `locations` WHERE `locations`.`type` IN ('TmplLocation') AND `locations`.`id` = ? LIMIT 1 [["id", 18]]
SQL (0.2ms) BEGIN
(0.7ms) UPDATE `locations` SET `location_id` = 23, `updated_at` = '2013-06-11 10:47:11' WHERE `locations`.`type` IN ('TmplLocation') AND `locations`.`id` = 18
(41.4ms) COMMIT
你看? 它會更新TmplLocation,因此現在它一直與這個確切的城市關聯。 我只想在此City中使用TmplLocation實例。如何跳過更新階段?
您可以嘗試這樣的事情
class City<ActiveRecord::Base
has_one :template, class_name:'TmplLocation', :conditions => { :id => 18 }
end
有關更多選項,請參見此
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