Python sql - 在结果为空的情况下重试执行查询

Question

Trying to get some data from DB using python sql library (PyODBCConnector). The Db is mysql. There is a situation where having an empty result (momentarily), but it will be very rare and on executing sql again the results will be available.

So trying to find a way to retry in case result-set is empty.

Found many examples but these retries are in case of any sql execution error.

any suitable example will be of great help.

Thanks in advance.

Answer 1

You can do something like this:

i = 0
keepGoing = 0
sql """some sql"""
while keepGoing < 3:
    for i in range(RETRIES):
        try:
            retval = 0
            conn = pyodbc.connect(get_mssql_conn_string(), autocommit=True)  # Don't remove the autocommit
            cursor = conn.cursor()
            cursor.execute(sql)
            fromMSSQL = cursor.rowcount
            conn.close()

        except Exception as e:
            config.LOG.info('Exception executing Stored Proc.')
            config.LOG.info(e)

        else:  # If your sql executes correctly, you only need to check if it returned any resultset
            if fromMSSQL == 0:
                keepGoing += 1
                print('I am going')
            else:
                break

so the while loop outside will keep going n times, unless your count is other than zero, which will cause it to break.