Question

我想查看客户的每个项目，但不确定如何使用Datamapper来获取此信息。我的关系设置如下：

class Client
    property :id, Serial
    property  :name, String
    has n, :projects, :foreign_key => "company_id"
end

class Project
  include DataMapper::Resource
  property :id, Serial
  property  :title, String
  belongs_to :company, "Client"
  has n, :stages
end

我想输出如下列表：

客户1

项目A
项目B
项目C

客户2

项目D
Project E

从Datamapper中获取此功能的最佳方法是什么？视图模板的外观是什么？

由于

Answer 1

# Find all clients (this should go in a controller of some kind)
@clients = Client.all # Maybe you want to order them here too

查看...

<% @clients.each do |client| %>
<%= client.name %>
<ul>
  <% client.projects.each do |project| %>
  <li><%= project.title %></li>
  <% end %>
</ul>
<% end %>

Answer 2

DataMapper没有foreign_key选项。这是:child_key

因此，您需要更改客户端模型

class Client
    property :id, Serial
    property  :name, String
    has n, :projects, 'Project', :child_key => [:company_id]
end

您可以按客户端迭代所有项目

<% Client.all.each do |client| %>
<%= client.name %>
<ul>
  <% client.projects.each do |project| %>
  <li><%= project.title %></li>
  <% end %>
</ul>
<% end %>

Datamapper - 按项目查找每个客户端

2 个答案: