如何在rails中将对象附加到关联关系中？

Question

在rails 4.1应用程序中，我需要向"AssociationRelation“添加一个对象

  def index
    employee = Employee.where(id_person: params[:id_person]).take
    receipts_t = employee.receipts.where(:consent => true) #gives 3 results 
    receipts_n = employee.receipts.where(:consent => nil).limit(1) #gives 1 result

    #I would need to add the null consent query result to the true consent results
    #something similar to this and the result is still an association relation
    @receipts = receipts_t + receipts_n

  end

有什么简单的方法吗？

Answer 1

解决这一问题的办法：

  def index
    employee_receipts = Employee.find_by(id_person: params[:id_person]).receipts
    receipts_t = employee_receipts.where(consent: true)
    receipts_n = employee_receipts.where(consent: nil).limit(1)

    @receipts = Receipt.where(id: receipts_t.ids + receipts_n.ids)
  end

不幸的是，这里不能使用.or()，因为它只能从Rails版本5.0.0.1中获得。

Answer 2

你可以这样做

receipts_t_ids = employee.receipts.where(:consent => true).pluck(:id)
receipts_n_ids = employee.receipts.where(:consent => nil).limit(1).pluck(:id)

@receipts = Receipt.where(id: receipts_t_ids + receipts_n_ids)

Answer 3

为了避免额外的查询和将数组保存在内存中，可以使用or

如下所示：

def index
  employee_receipts = Employee.find_by(id_person: params[:id_person]).receipts

  @receipts =
    employee_receipts.where(consent: true).or(
      employee_receipts.where(consent: nil).limit(1)
    )
end