Question

I’ve got two models:

Customer and Contact

Customers table has columns :id, :firstName, :lastName

Contacts table has columns :id, :cid, :hphone, :cphone

So if Customers table has data

1  Josh   McDonnel

Then Contacts table has corresponding

5   1   947-245-2342 342-543-8585 

What associations can I use here?

Will Contact have

belongs_to :customer, :foreign_key => "id", :class_name => "Customer"

What should the Customer class have?

Also, how will a simple find_byXXX look like if I want to get all customers (firstName, lastName and corresponding hphone and cphone)

Answer 1

You are close, but your belongs_to should be this. :foreign_key should be the name of the field storing a reference to the primary id:

belongs_to :customer, :foreign_key => "cid"

And in your Customer.rb class:

has_one :contact, :foreign_key => "cid"

Finally, your search might look like this:

@customers = Customer.all(:include => :contact)

Then you could use it in a loop in your view:

<% @customers.each do |customer| %>
   <p>Name: <%= customer.firstName %> <%= customer.lastName %></p>
   <p>Home: <%= customer.contact.hphone %></p>
   <p>Work: <%= customer.contact.cphone %></p>
<% end %>

Incidentally, if you had used customer_id instead of cid your association could just be:

#Contact.rb
belongs_to :customer

#Customer.rb
has_one :contact