python MySQLdb simple usage

import MySQLdb
import _mysql_exceptions

......
goaldb = MySQLdb.connect(user=dbuser, passwd=dbpass, host=dbhost, port=dbport, db=dbname)
SQL = "select ..."
goaldb.query(SQL)
rows = goaldb.store_result().fetch_row(maxrows=0)
if rows:
    for r in rows:
        ......
    SQL = "update ..."
    goaldb.query(SQL)
else:
    SQL = "insert ..."
    goaldb.query(SQL)

except _mysql_exceptions.ProgrammingError, (errno, errstr):
    strerr = "SQL Error: %d, %s" % (errno, errstr)
    print strerr >> sys.stderr
except _mysql_exceptions.MySQLError, (errno, errstr):
    strerr = "MySQL DB Error: %d, %s" % (errno, errstr)
    print strerr >> sys.stderr