Ruby-on-rails 带有自定义外键的 Rails own_to has_many

Rails belong_to has_many with a custom foreign key

提问by Drahcir

I have a relationship between 2 models in my rails application. I have veered away from the standard of how to implement the relationship as I used another field as a primary key and the naming convention is different. Doing so resulted in the relationship seemingly not being established. I want to understand as to why.

我的 rails 应用程序中有 2 个模型之间的关系。我已经偏离了如何实现关系的标准，因为我使用另一个字段作为主键并且命名约定不同。这样做导致这种关系似乎没有建立。我想了解为什么。

This is a trimmed down version of my models:

这是我的模型的精简版：

class Player < ActiveRecord::Base
  set_primary_key "alias"
  attr_accessible :alias, :avatar
  has_many :player_sessions, :foreign_key => "player_alias", :class_name => "PlayerSession" 
end

class PlayerSession < ActiveRecord::Base
  attr_accessible :player_alias, :total_score
  belongs_to :player, :foreign_key  => "player_alias", :class_name => "Player" 
end

The Playermodel has the field aliaswhich is the username in my application. I wanted the username to act as the primary key since it is unique and it would be easier to migrate the data and maintain relationships.

该Player模型的字段alias是我的应用程序中的用户名。我希望用户名充当主键，因为它是唯一的，并且可以更轻松地迁移数据和维护关系。

Originally I only had PlayerSession model with data already filled in, but as my application grew I added the Player model and simply inserted a row with the same alias.

最初我只有已经填充了数据的 PlayerSession 模型，但是随着我的应用程序的增长，我添加了 Player 模型并简单地插入了一行具有相同alias.

In the Player's showview I have the following code:

在Player的show视图中，我有以下代码：

Player Sessions:
<% @player.player_sessions do |player_session| %>
<ul>
    <li><h4>Highest Score:</h4> <%= player_session.total_score %> </li>
</ul>

When I try to access the page it simple doesn't show the information.

当我尝试访问该页面时，它很简单不显示信息。

Other information I can add is that I haven't added any relationships in the database itself.

我可以添加的其他信息是我没有在数据库本身中添加任何关系。

I am still new to rails and still playing around with it. Any opinions that concern coding standards(outside from answering the question) are welcome.

我对 Rails 还是个新手，还在玩它。欢迎任何有关编码标准的意见（除了回答问题）。

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UpdateI have implemented Babur Usenakunov's suggestion by adding the primary_keyoption in the models:

更新我通过primary_key在模型中添加选项来实现 Babur Usenakunov 的建议：

class Player < ActiveRecord::Base
  set_primary_key "alias"
  attr_accessible :alias, :avatar
  has_many :player_sessions, :primary_key => "alias", :foreign_key => "player_alias", :class_name => "PlayerSession" 
end

class PlayerSession < ActiveRecord::Base
  attr_accessible :player_alias, :total_score
  belongs_to :player, :primary_key => "alias", :foreign_key  => "player_alias", :class_name => "Player" 
end

Also to test out the the data is valid I acquired the PlayerSession list manually:

同样为了测试数据是否有效，我手动获取了 PlayerSession 列表：

Code implemented in controller:

在控制器中实现的代码：

@player_sessions =  PlayerSession.where("player_alias = ?", params[:id])

Code implemented in view(which outputs the data):

在视图中实现的代码（输出数据）：

<% @player_sessions.each do |player_session| %>
<ul>
    <li><h4>Highest Score:</h4> <%= player_session.total_score %> </li>
</ul>
<% end %>

采纳答案by Drahcir

I have solved the issue, it was a matter of adding eachin the loop I implemented in the view:

我已经解决了这个问题，这是each在我在视图中实现的循环中添加的问题：

<% @player.player_sessions.each do |player_session| %>
<ul>
    <li><h4>Highest Score:</h4> <%= player_session.total_score %> </li>
</ul>    
<% end %>

After playing around a bit, I realised i didn't need to add the primary_key option in either of the views, and left the foreign key option only in the Playermodel.

玩了一会后，我意识到我不需要在任何一个视图中添加 primary_key 选项，而只在Player模型中保留外键选项。

class Player < ActiveRecord::Base
  set_primary_key "alias"
  attr_accessible :alias, :avatar
  has_many :player_sessions, :foreign_key => "player_alias", :class_name => "PlayerSession" 
end

class PlayerSession < ActiveRecord::Base
  attr_accessible :player_alias, :total_score
  belongs_to :player, :class_name => "Player" 
end

回答by marcelowiermann

If your PlayerSession table has a column named aliasthen your foreign key should also be alias, not player_alias. As a token of advice I'd be wary of using an alias as a foreign_key: if your player can/decide to change his alias then all PlayerSession records within your database will become invalid and require an update. Using an immutable parameter such as player_idwould be preferable to using the existing alias column IMHO.

如果您的 PlayerSession 表有一个名为的列，alias那么您的外键也应该是alias，而不是player_alias。作为建议，我会谨慎使用别名作为外键：如果您的玩家可以/决定更改他的别名，那么您数据库中的所有 PlayerSession 记录都将无效并需要更新。使用不可变参数，例如player_id使用现有别名列恕我直言更可取。