CakePHP containable doesn't filter in a proper way

Question

Like the example in cakephp manual, http://book.cakephp.org/view/1323/Containable#Containing-deeper-associations-1325, i need to fetch data from a model through a condition on its association model.

I have:

Model Language:

class Language extends AppModel {

    var $name = 'Language';
    var $actsAs = array('Containable');

        var $hasMany = array(
        'LanguageTranslation' => array(
            'className' => 'LanguageTranslation',
            'foreignKey' => 'language_id'
        )
    );

}

And the association, ModelTranslation

class LanguageTranslation extends AppModel {

    var $name = 'LanguageTranslation';

    var $belongsTo = array(
        'Language'
    );
}

when i do:

$language_array = $this->controller->Language->find('all', array(
            'contain' => "LanguageTranslation.id = 1" 
        ));

i receive all the languages, not only one (because id in LanguageTranslation is unique). The result need to be one!

SO, with

debug($language_array);

result is:

Array
(
    [0] => Array
        (
            [Language] => Array
                (
                    [id] => 1
                    [code] => it
                    [locale] => ita
                )

            [LanguageTranslation] => Array
                (
                    [0] => Array
                        (
                            [id] => 1
                            [language_id] => 1
                            [language] => italiano
                        )

                )

        )

    [1] => Array
        (
            [Language] => Array
                (
                    [id] => 2
                    [code] => en
                    [locale] => eng
                )

            [LanguageTranslation] => Array
                (
                )

        )

    [2] => Array
        (
            [Language] => Array
                (
                    [id] => 3
                    [code] => de
                    [locale] => ger
                )

            [LanguageTranslation] => Array
                (
                )

        )
)

Why i don't catch only the Language with id = 1?

Answer 1

The conditions in containable apply only to the models inside the containment. Because the main query doesn't have any conditions it fetches every row in the table. In general you don't use containable to restrict the main query but to limit the way the query goes through the containment tree (very handy when you need to go through 3-4 levels of recursiveness where the results can get quite bloated if not contained).

In this case in particular if you are trying to get the data of a certain Language/LanguageTranslation pair, you can just pull the data from the LanguageTranslation model.

$this->Language->LanguageTranslation->find( 
    'first',
    array( 
        'conditions' => array( 'LanguageTranslation.id' => 1 ),
        'recursive'  => 1
    )
);