what is local key in laravel eloquent

Question

http://laravel.com/docs/4.2/eloquent#relationships

what does local key mean in this thing? does it mean primary key of the table? or what? for example in this code

return $this->hasOne('Phone', 'foreign_key');

return $this->hasOne('Phone', 'foreign_key', 'local_key');

Answer 1

local_key is the primary key of your table. You only need to specify it if your primary key is not called id AND you do not have the $primaryKey property set in your model.

Answer 2

I believe everything is written in the doc:

ake note that Eloquent assumes the foreign key of the relationship based on the model name. In this case, Phone model is assumed to use a user_id foreign key. If you wish to override this convention, you may pass a second argument to the hasOne method. Furthermore, you may pass a third argument to the method to specify which local column that should be used for the association:

Which basically means that 'local_key' is the name of the table column in your db which is responsible to match the related entity (phone) with your current entity (user).

If you have a look at the db, I'm sure you'll find a table user with a phone_id column, try to change it to something else (like "phone" only) and your eloquent request will crash. Then change your call to return $this->hasOne('Phone', 'user_id', 'phone'); and this might work again.