ruby-on-rails - 从 exec_query 实例化 STI 继承模型结果

Question

给定返回哈希的查询:

def query
  sql = %(SELECT * FROM components
          INNER JOIN brands_components ON brands_components.component_id = components.id
          INNER JOIN brands ON brands.id = brands_components.brand_id
          INNER JOIN components_templates ON components.id = components_templates.component_id
          WHERE components_templates.template_id = #{@template.id}
          AND (components.user_id IS null OR components.user_id = #{@user.id})
          AND brands.id = #{@user.brand_id})
  ActiveRecord::Base.connection.exec_query(sql)
end

如何将结果实例化为 ActiveRecord 集合(尤其是当它们代表不同的模型时[即，STI 继承自 Component])？

Answer 1

将 sql 传递给 find_by_sql将实例化模型，因此将方法更改为

def query
  sql = [some sql]
  Component.find_by_sql(sql)
end

应该给你你想要的。它还将为每条记录实例化正确的子类。