public function getIndexDeclarationSQL($name, Index $index)
    {
        $columns = $index->getQuotedColumns($this);
        $name = new Identifier($name);

        if (count($columns) == 0) {
            throw new \InvalidArgumentException("Incomplete definition. 'columns' required.");
        }

        return 'INDEX ' . $name->getQuotedName($this) . ' USING FULLTEXT ('. $this->getIndexFieldDeclarationListSQL($columns) . ')';
    }