public function findHighestWeight(Garp_Model $model, $foreignKey, array $modelRelationConfig) {
        $foreignKeyColumn = $model->getAdapter()->quoteIdentifier($modelRelationConfig[self::FOREIGN_KEY_COLUMN_KEY]);
        $weightColumn     = $model->getAdapter()->quoteIdentifier($modelRelationConfig[self::WEIGHT_COLUMN_KEY]);
        $select = $model->select()
                        ->from($model->getName(), array('max' => 'MAX('.$weightColumn.')'))
                        ->where($foreignKeyColumn.' = ?', $foreignKey)
                        ;

        $result = $model->fetchRow($select);
        if ($result && $result->max) {
            return $result->max;
        }
        return 0;
    }