:return: the list of column in this table

def columns(self):
        """
        :return: the list of column in this table
        """
        c = self._connection.cursor()
        c.execute("describe `%s`.`%s`" % (self._db, self._name))
        self._cols = []
        for col in c.fetchall():
            self._cols.append(Column.build(col, table=self, con=self._connection))
        return self._cols