private function getColumnComments()
    {
        $escapement = new Escapement();
        $comments = '';
        foreach ($this->table->getColumns() as $column) {
             $columnDescription = $column->getDescription();
             if (!empty($columnDescription)) {
                $comments .= sprintf("COMMENT ON COLUMN %s.%s IS '%s';",
                    $escapement->escape($this->table->getQualifiedName()),
                    $escapement->escape($column->getName()),
                    $columnDescription);
             }
        }

        return $comments;
    }