How to build a relation in yii 1.x not by pk?

Question

MySQL

There are two tables:
Specifications
id, key, name, category, lang
SpecificationsCategories
id, key, name, lang
The categories model is written like this:

public function relations()
    {
        return [
            'specification'=>[self::HAS_MANY, 'Specifications', 'category',
                'on'=>'t.lang = specification.lang',
                'joinType' => 'inner join',
            ],
        ];
    }

But the bundle goes t.id = specification.category. I did not find a parameter with which you can specify the key.
How to explain to Yii that I need to bind like t.key = specification.category?

Answer 1

third parameter in relation array ['id' => 'category']