Multiple Reference To Same External Table in Yii - php

Question

I'm quite new to Yii development and I find myself stuck at the very beginning..
In my project I have a table with two columns both pointing to an external table.
Something like:
table "item":
- user_id_1
- user_id_2
table "user":
- id
So an item i always associated with two users, but I do not want to differentiate them, and I want to be able to do something like
$item->users
getting both the users.
And also the opposite:
$user->items
getting all items that reference the user id in user_id_1 or user_id_2.
Does this sound right? Any suggestion?

Answer 1

Yii's ActiveRecord is really only set up to handle one-to-one and one-to-many relationships - you seem to be describing a one-to-two relationship.
One way to handle this would be to set up a MANY_MANY relationship, but just use it with two users instead of "many". You will need to set up a user_item table that connects Users to Items, instead of embedding the key directly in the tables. If you need to enforce only two Users-to-an-Item you'll need to write some extra Validation code in your Item model. The relation in Item will look something like this, and you will be able to call $item->users like you want:
public function relations() {
return CMap::mergeArray(parent::relations(),array(
'users'=>array(self::MANY_MANY, 'User', 'user_item(item_id,user_id)'),
));
}
The new associative table will look like this:
user_item:
-- user_id
-- item_id
If you really need to use two separate user_id foreign key fields like you have here, you will need to set up an ActiveRecord HAS_ONE relation for each, like so:
public function relations() {
return CMap::mergeArray(parent::relations(),array(
'user1' => array(self::BELONGS_TO, 'User', 'user_id_1'),
'user2' => array(self::BELONGS_TO, 'User', 'user_id_2'),
));
}
But, you can still enable the $item->users call syntax with a function something like this, which will return both users in a single array:
public function getUsers() {
return array(
$this->user1,
$this->user2,
);
}
This takes advantage of Yii's __get() method override, which will allow you to call $item->getUsers() like $item->users.
You can set up something similar in the User model, with two HAS_MANY relations for user_id_1 and user_id_2, and a getItems method which returns the merged result arrays.
But I think the easiest option will be to set up a MANY_MANY relationship (and use it a ONE_TWO relation).