在Rails中创建关联

Question

I've got model Project and model User. I've got belongs_and_has_many in these. But now I need to tell Rails: this specific user belongs to this specific project. How can I do it in Project controller, and how can I call this method from project view? Thank you very much.

in project's* show.html.erb * I ve got:

<select id="user_select" name="user_select" class="input-large">
  <% @users.each do |user| %>
    <option><%= user.username %></options>
  <% end %>
</select>
<!-- button to addfriend method here -->

And I need to call method "addfriend" from here with parameter from selection to associated project with this user :-/

Method addfiend in project controller:

def addfriend
      @project = Project.find(params[:id])
      @project.users << User.find(params[:user])
      respond_to do |format|
        format.html { redirect_to project, :notice => 'Added.' }
      end
end

Answer 1

如果在模型项目中，您具有has_and_belongs_to_many :users ，则您的项目对象具有隐式collection用户，可以像其他任何collection一样将其添加，例如：

project.users << User.find(:first, :conditions => "name = 'foo'")

Answer 2

This would look something like that in your controller action:

@project = Project.create(:user_id => user_id)

while user_id is your foreign key (something you would probably want to pass from your view).

This code will be written in some controller action, and you would have to define a route for connecting a URL to this action.

Notice that once you call the action that runs this code you can access @project from your view.

You can read about routes here . You can read about mvc in rails here . You can read about associations here: http://guides.rubyonrails.org/association_basics.html