Self-Referencing Relationships

lhagemann · August 2013

I"m trying to figure out if any of the built-in relationships can be used to implement a self-referencing one-to-many relationship.

I have "Projects" which belong to "Customers" (Projects Module will have foriegn_key => customers_module).

Now a Project can have "related projects", which would be a one-to-many relationship back to it's own table. This is not a "foreign key" by definition, but foreign_key is the only relationship that represents a one-to-many. [side note: I have a tough time remembering that 'has_many' is a many-to-many relationship. In the above example I would naturally think "a customer has many projects"]

I haven't started building my modules yet, still drawing out the database relationships, but I'm thinking about the Model definitions as part of the modeling. Can I use something like


class Projects_model extends Base_module_model
{
public $foreign_keys  = array('id' => array(FUEL_FOLDER => 'projects_model')));

function __construct()
  {
    parent::__construct('projects');
  }
}

admin · August 2013

Were you planning on storing those related projects in their own table to lookup? If so, you should be able to use has_many to do this and it would store it in the fuel_relationships table. The blog module uses this to relate posts to other posts.
public $has_many = array('related_projects' =>'projects_model');

Lance · August 2013

Just another nod for this approach, I used it to relate products to other products (and other things), EG:



	public $has_many = array(
		'products' => array(
			'model' => array(STORE_FOLDER => 'products_model')
		),
		'categories' => array(
			'model' => array(STORE_FOLDER => 'categories_model')
		),
		'brands' => array(
			'model' => array(STORE_FOLDER => 'brands_model')
		),
		'manufacturers' => array(
			'model' => array(STORE_FOLDER => 'manufacturers_model')
		)
	);

Howdy, Stranger!

Categories

Self-Referencing Relationships

Comments