protected function getColumnCommentSqlDefinition(Column $column, $tableName)
    {
        // passing 'null' is to remove column comment
        $currentComment = $this->getColumnComment($tableName, $column->getName());

        $comment = (strcasecmp($column->getComment(), 'NULL') !== 0) ? $this->getConnection()->quote($column->getComment()) : '\'\'';
        $command = $currentComment === false ? 'sp_addextendedproperty' : 'sp_updateextendedproperty';

        return sprintf(
            "EXECUTE %s N'MS_Description', N%s, N'SCHEMA', N'%s', N'TABLE', N'%s', N'COLUMN', N'%s';",
            $command,
            $comment,
            $this->schema,
            $tableName,
            $column->getName()
        );
    }