Ruby On Rails-通过关联的新模型对象

Question

I have three models "Event", "Team", and "User" with various ActiveRecord Associations and am having trouble creating a new Event object and associating it with a team_id. Perhaps I am missing something with the relationships. They are defined as follows:

class User < ActiveRecord::Base
  has_many :teams
  has_many :events, through: :teams
end

class Team < ActiveRecord::Base
  has_many :events
  has_many :users
end

class Event < ActiveRecord::Base
  belongs_to :team
  has_many :users, through: :teams
end

class EventsController < ApplicationController
  def new
    @event = Event.new
  end

  def create
    @event = current_team.events.build(event_params)
    if @event.save
      flash[:success] = "Event created!"
      redirect_to @event
    else
      render 'new'
    end
  end

class TeamsController < ApplicationController
  def new
    @team = Team.new
  end

  def create
    @team = current_user.teams.build(team_params)
    if @team.save
      flash[:success] = "Team created!"
      redirect_to @team
    else
      render 'new'
    end
  end

The error is triggered in the events controller when I submit the create new event form, as current_team.events isn't recognized. I am relatively new to RoR so any help would be greatly appreciated!

Answer 1

From your code, it seems that current_team is not defined in your EventsController . If you get the team id from the form, you could do something like this:

current_team = Team.find(params[:team_id])

And then it should work.

Answer 2

Do you have an join table between User and Team? From that example you have many-to-many relationship between these two models but I dont see the relationship defined. Check the Rails guides

Answer 3

In the Team model, as it the join table you should do the following

class Team < ActiveRecord::Base
      belongs_to :event
      belongs_to :user
end

In the Event model :

class Event < ActiveRecord::Base
  has_many :teams
  has_many :users, through: :teams
end

Still I don't know if that what you really wants, if Team table is a join table and you want it to act like one, then this should be fine, but I suggest you check your relations again and also checking rails guide to completely understand what you have to do here

Answer 4

I finally figured out what was going on. I was trying to define current_team the same way one would define current_user, however, current_user is simply the one user in the current logged-in session.

Thus, I went a different route and passed the team_id parameter in the link_to the form for a new event. This allowed me to call the team_id in a hidden_field in the form and save it to the DB.

The method is explained quite well in this response: Pass Parameters in Link_to

Thanks for all of the help!

Events Controller

class EventsController < ApplicationController
 def new
    @event = Event.new(:team_id => params[:team_id])
 end

 def create
    @event = Event.new(event_params)
    if @event.save
      flash[:success] = "Event created!"
      redirect_to @event
    else
      render 'new'
    end
 end

 private

  def event_params
      params.require(:event).permit(:date, :name, :location, :venue, :team_id)
    end
end

link:

<%= link_to "Create new event", newevent_path(:team_id => @team.id), class: "btn btn-md" %>

hidden field in form

<%= f.hidden_field :team_id %>