If you want to set up a 1-1 relationship between two models, you'll need to add +belongs_to+ to one, and +has_one+ to the other. How do you know which is which?
If you want to set up a 1–1 relationship between two models, you'll need to add +belongs_to+ to one, and +has_one+ to the other. How do you know which is which?
The distinction is in where you place the foreign key (it goes on the table for the class declaring the +belongs_to+ association), but you should give some thought to the actual meaning of the data as well. The +has_one+ relationship says that one of something is yours - that is, that something points back to you. For example, it makes more sense to say that a supplier owns an account than that an account owns a supplier. This suggests that the correct relationships are like this:
