Basic database association - ruby-on-rails

Question

I am attempting to associate 2 models - Athletes and Results
They have the following fields:
Athletes - :name :year :gender
Results - :name :event :performance
I have added belongs_to :athlete to results.rb & added has_many :results to athletes.rb
I would like to use the :name attribute to act as the primary key used to associate the two models as the intention is for all athletes to be uploaded initially and then just use the results input for the remainder of the season.
I have edited the results_controller to the following:
def create
#this was the initial code....
##result = Result.new(params[:result])
# This is the new code to try set up an association
#athlete = Athlete.where('name = ?', 'Peter')
#result = #athlete.results.create(params[:result])
respond_to do |format|
if #result.save
format.html { redirect_to #result, notice: 'Result was successfully created.' }
format.json { render json: #result, status: :created, location: #result }
else
format.html { render action: "new" }
format.json { render json: #result.errors, status: :unprocessable_entity }
end
end
end
This however produces the error undefined method 'results' for #<ActiveRecord::Relation:0x36a2b28>. I was also hoping to use the line #athlete = Athlete.where("name = ?", params[:name]) however it keeps yielding a NULL parameter value...
Is anyone able to point me in the correct direction please?
Extra information:
Results migration
class CreateResults < ActiveRecord::Migration def change
create_table :results do |t|
t.string :name
t.string :event
t.decimal :performance
t.timestamps
end
#add in new line here
add_index :results, :name
end end
Athletes migration
class CreateAthletes < ActiveRecord::Migration
def change
create_table :athletes do |t|
t.string :name
t.integer :year
t.string :gender
t.timestamps
end
end
end
Result.rb:
class Result < ActiveRecord::Base
belongs_to :athlete
end
Athlete.rb
class Athlete < ActiveRecord::Base
has_many :results
end

Answer 1

The problem is that Athlete.where('name = ?', 'Peter') returns ActiveRecord::Relation object. Either use
Athlete.where('name = ?', 'Peter').first
or the dynamic find method
Athlete.find_by_name('Peter')
Edit
Also make sure you add t.references :athlete to your results table.

Answer 2

Your results table needs to store the athlete_id.
create_table :results do |t|
t.references :athlete
t.string :name
t.string :event
t.decimal :performance
t.timestamps
end
The references will create the foreign key association using the rails conventions (which in this case is athlete_id)