Hey, I have this code. So I don't understand to change this code to ORM. So give me some advice! Thanks so much.

@api.model
def compute_pattern(self, pattern, field):
    sql = """
            SELECT %s
            FROM product_material
            WHERE %s LIKE '%s%%'
            ORDER BY %s DESC
            LIMIT 1
        """ % (field, field, pattern, field)
    self._cr.execute(sql)
    sql_result = self._cr.fetchone()
    sql_result = sql_result and sql_result[0] or False
    if not sql_result:
        return pattern + '001'
    digit = sql_result.split(pattern)[1]
    digit = str(int(digit) + 1)
    while len(digit) < 3:
        digit = '0' + digit
    return pattern + digit