skeeks\cms\models\CmsContentElementTree::rules PHP Method

    public function rules()
    {
        return array_merge(parent::rules(), [[['created_by', 'updated_by', 'created_at', 'updated_at', 'element_id', 'tree_id'], 'integer'], [['element_id', 'tree_id'], 'required'], [['element_id', 'tree_id'], 'unique', 'targetAttribute' => ['element_id', 'tree_id'], 'message' => \Yii::t('skeeks/cms', 'The combination of Element ID and Tree ID has already been taken.')]]);
    }