many to one relation.

rubyonrails-talk
1

-i searched through the news group but couldn't find the answer for my problem. example:

----------- classes ---------- class Car < ActiveRecord::Base   has_one :colour   def after_create()     colour = Colour.new     colour.name = 'colour1'     colour.save   end end

class Chair < ActiveRecord::Base   has_one :colour end

class Colour < ActiveRecord::Base end -------------- tables --------- create table cars(id int PRIMARY KEY NOT NULL AUTO_INCREMENT,name varchar(50),colour_id int NOT NULL, primary key(id));

create table chairs(id int PRIMARY KEY NOT NULL AUTO_INCREMENT,name varchar(50),colour_id int NOT NULL);

create table colours(id int PRIMARY KEY NOT NULL AUTO_INCREMENT,name varchar(50));

- i consider it a many to one relation because diferent types of items are refering to one type (Car and Chair both have colour). - i wrote the models as above i create a Car object, i save it but alwayes my colour_id in the database remains 0.   I would appreciate if your could give me a hint.

2

When you say “car has one colour”, the other side of the relationship must read “colour belongs to car”. Now the entity that has the belongs to relationship is the one which will have the foreign key, in this case it will be car_id.

So, your tables must define the foreign keys prperly and also declare the belongs to relationship. Make the changes and run again and see if the record gets populated.