rails:创建父级，如果不存在，则创建子级记录 [英] rails: create Parent, if doesn't exist, whilte creating child record

问题描述

是否有以下最佳做法?

我的制造商模型具有很多库存

I have Manufacturer model that has_many Inventory

在我的新清单表单中，我想要一个映射到Manufacturer.name的字段，以便当一个 提交新清单的应用程序:

In my new Inventory form I want a field that maps to Manufacturer.name so that when one submits the new Inventory form the app:

• 从表格中搜索带有名称"的制造商
  • 如果存在，则将ID分配给@ inventory.manufacturer_id并保存@inventory
  • 如果不存在，则从表单中使用名称"创建制造商，将ID分配给@ inventory.manufacturer_id并保存
  • 在新的库存表单上进行了验证
    • 这样，如果库存"表单在名称"以外的其他字段上的验证失败
      • 名称"字段将用用户输入的任何内容重新填充(但除非表单通过验证，否则不会创建新的制造商)
      • searches for a manufacturer with the 'name' from the form
        • if it exists then assign the id to @inventory.manufacturer_id and save @inventory
        • if it doesn't exist then create the manufacturer with the 'name' from the form, assign the id to @inventory.manufacturer_id and save
        • have validations work on the new Inventory form
          • such that, if the the Inventory form fails validation on a field other than 'name'
            • the 'name' field will be repopulated with whatever the user entered (but a new manufacturer is not created unless the form passes validation)

            推荐答案

            您可以这样尝试:

            class Inventory < ActiveRecord::Base
            
              ...
            
              belongs_to :manufacturer
            
              ...
            
              def manufacturer_name
                manufacturer && manufacturer.name
              end
            
              def manufacturer_name=(value)
                self.manufacturer = Manufacturer.find_by_name(value)
                self.manufacturer ||= Manufacturer.new(:name => value)
              end
            
              ...
            
            end
            

            在这种情况下，您应该在库存"表单上输出制造商名称文本字段.

            In this case you should output manufacturer_name text field on Inventory form.

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