Question

我有一个具有默认范围的模型

class SomeModel < ActiveRecord::Base
  attr_accessible :id, :name
  default_scope includes(:relation)

  after_initialize :do_something_with_relation

  def do_something_with_relation
    self.name += self.relation.name
  end
end

我在这里尝试做的是将关系的名称附加到SomeModel对象。我添加了一个默认范围来支持预先加载。但由于某种原因，尽管需要加载，但是使用where子句获取的每个对象都会获取该关系。

SomeModel.where("name LIKE '%some name%'").all


SomeModel Load (0.2ms)  SELECT `some_models`.* FROM `some_models`
SomeRelation Load (0.2ms)  SELECT `some_relations`.* FROM `some_relations` WHERE `some_relations`.`id` = some_id LIMIT 1
SomeRelation Load (0.2ms)  SELECT `some_relations`.* FROM `some_relations` WHERE `some_relations`.`id` = some_id LIMIT 1
SomeRelation Load (0.2ms)  SELECT `some_relations`.* FROM `some_relations` WHERE `some_relations`.`id` = some_id LIMIT 1
SomeRelation Load (0.2ms)  SELECT `some_relations`.* FROM `some_relations` WHERE `some_relations`.`id` = some_id LIMIT 1

这是一个优先问题吗？在对象初始化之后发生了急切的加载？如果有，有办法在预先加载完成后触发after initialize回调吗？

我期待的结果是

SomeModel Load (0.2ms)  SELECT `some_models`.* FROM `some_models`
SomeRelation Load (0.2ms)  SELECT `some_relations`.* FROM `some_relations` WHERE `some_relations`.`id` IN (some_id, some_other_id, ...)

我正在使用Rails 3.2

Answer 1

在设置预加载关联之前调用

after_initialize，因此您只需在获取所有内容后手动调用自定义方法

应用默认范围后在模型中初始化后触发

1 个答案: