使用has_many:through创建联接记录 [英] Creating joined records using has_many :through

问题描述

好吧，我认为我很好地遵循了这个答案...

Ok I thought I was following this answer pretty well... how to add records to has_many :through association in rails. But clearly not.

型号代码:

class Transaction < ActiveRecord::Base
  belongs_to :request
  has_many :transactories
  has_many :inventories, through: :transactories
end

class Inventory < ActiveRecord::Base
  has_many :transactories
  has_many :transactions, through: :transactories
end

class Transactory < ActiveRecord::Base
  belongs_to :inventory
  belongs_to :transaction
end

我基本上是在尝试将存货与交易(有货的人，或有货的人)进行匹配

I'm basically trying to match inventories with transactions (people who have stuff, with people who want that stuff)

这是我要实现的流程:

1. 用户在哈希中提供数据，其中键=他们想要的itemlist_id，值=他们想要的itemlist_id的quantity.假设用户想要9个中的两个，如下所示:{ 9 => 2}
2. 对于用户提供的哈希中的每个itemlist_id，我将查看Inventories table的内部，并拉出inventory_ids，其中itemlist_id与用户要查找的内容以及该所有者的所有者inventory_id不是用户他或她自己.假设在Inventories table中，有3个ID可以满足此要求:[X, Y, Z]

3. 现在我要做的是创建Transactions并将Transactions和Inventories相互关联.此步骤的结果有两个方面(我认为从视图的外观来看更容易编写:

1. User provides data in a hash where key = the itemlist_id of what they want and the value = the quantity of that itemlist_id that they want. Let's say user wants two of 9, that would look like this: { 9 => 2}
2. For each itemlist_id in the user provided hash, I'm going to look inside the Inventories table and pull out the inventory_ids where the itemlist_id matches what the user is looking for and the owner of that inventory_id is not the user him or herself. Let's say that in the Inventories table, there are 3 ids that fulfill this: [X, Y, Z]

3. Now what I'd like to do is create the Transactions and associate the Transactions and Inventories with each other. The outcome of this step is two-fold (I think it's easier to write from the perspective of what the view will look like:

• 每个X，Y和Z inventory_id的所有者应看到他们的物品有2个transactions(以便他们可以选择要尊敬的一个)
• 用户可以看到他们的2个transactions中每个X，Y和Z的所有者都收到了通知

• that the owner of each X, Y, and Z inventory_id should see that there are 2 transactions for their item (so they can pick which one they want to honor)
• that the user can see that for each of their 2 transactions, there are notifications to the owners of each X, Y, and Z

创建关联的代码

# Assume overarching parent request has been created, called @requestrecord
# Step 1, @transactionparams = { 9 => 2 }
@transactionparams.each do |itemlist_id, quantity|
# Step 2 matched_inventory_id = [X,Y,Z] 
      matched_inventory_id = Inventory.where.not(signup_id: @requestrecord.signup.id).where(itemlist_id: itemlist_id).ids 
# Step 3, 2 transactions created each with itemlist_id of 9, each associated with inventory_ids X, Y, Z. In turn, inventory_ids X, Y, Z each associated with each of the two transactions created
      quantity.to_i.times do
        transaction = @requestrecord.transactions.create(itemlist_id: itemlist_id) 
        transaction.inventories.create matched_inventory_id
      end
    end

第3步使我绊倒.代码停留在transaction.inventories.create行，并且出现错误:uninitialized constant Transaction::Transactory

Step 3 is tripping me up. The code is stuck at the transaction.inventories.create line and I'm getting an error: uninitialized constant Transaction::Transactory

更新

现在，我陷入了错误You tried to define an association named transaction on the model TransactionInventory, but this will conflict with a method transaction already defined by Active Record. Please choose a different association name.的问题，我尝试指定class_names和foreign_keys，请参见以下示例:

Now I'm stuck at the error You tried to define an association named transaction on the model TransactionInventory, but this will conflict with a method transaction already defined by Active Record. Please choose a different association name. I tried specifying class_names and foreign_keys, see example below:

belongs_to :transaction, foreign_key: "transaction_id", class_name: "Transaction"

推荐答案

您在

transaction.inventories.create matched_inventory_id

顺便说一句，它应该是matched_inventory_ids，因为ids方法始终返回一个数组

And by the way it should be matched_inventory_ids because the ids method returns allways an array

others.create方法不接受id或id的数组.在这种情况下，它将接受广告资源的属性

The others.create method does not accept id or an id's array. It will accept attributes of the inventory in that case

要使用id进行关联，请使用other_ids方法

To do association by id use the other_ids method

transaction.inventory_ids = transaction.inventory_ids + matched_inventory_ids 

这篇关于使用has_many:through创建联接记录的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！