Rails - Retrieve data from multiple tables

Question

I have read so much about Rails in the past week in the process of trying to learn it. The problem is when I need something I find it difficult to recall where I read it! ha ha

I have two models: Guest and Booking where Guests has_many Bookings. Therefore the Booking model has a guest_id field included.

I would like to retrieve all the booking data and the guest data and display in a view as one object. I know I have seen a simple solution to this (in the Rails doc I think) that does just this.

At the moment I'm doing the following in my BookingsController:

@bookings = Booking.all

and in my associated view I have:

<% @bookings.each do |booking| %>
  <p><%= booking.id %></p>
  <p><%= booking.email %></p> //this does not work as email is in guests table!!!
<% end %>

but how can I get the linked Guest table included too?

Tero Tilus · Accepted Answer · 2013-09-08 09:12:33Z

2

If your booking belongs to guest

class Booking < ActiveRecord::Base
  belongs_to :guest
  ...
end

you can first include guest to avoid n+1 queries

@bookings = Booking.includes(:guest).all

and then in view, traverse the association

<% @bookings.each do |booking| %>
  <p><%= booking.id %></p>
  <p><%= booking.guest.email %></p>
<% end %>

edited Sep 8, 2013 at 9:12

Tero Tilus

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answered Sep 8, 2013 at 8:56

zolter

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1 Comment

tommyd456 Over a year ago

Fantastic - and went to extra length to show me example. Cheers for the help

ekremkaraca · Accepted Answer · 2013-09-08 08:55:54Z

1

In your bookings controller:

@bookings = Booking.includes(:guest).all

answered Sep 8, 2013 at 8:55

ekremkaraca

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