python - Raise Exception when WHERE doesn't exist during UPDATE query -

i'm using mysqldb / python api project , ran problem:

def activate_acct(act_link):      # connect     db = mysqldb.connect(host=db_host, user=db_user, passwd=db_pass,  db=db_name)      # create database cursor     cursor = db.cursor()      try:         sql = """update users         set activated = %s         activate_code = %s"""          cursor.execute(sql, (1, act_link))         db.commit()          return "activated"      except exception e:          return e 

the query works, in when activate_code found, activated changed, db updated want, , see success message. problem if activate_code doesn't exist and/or invalid, still success message.

how can have query raise exception if activate_code isn't found where?

an update statement changes nothing still considered successful. told database make change wherever found value; value found nowhere, change made nowhere. did asked.

if want check make sure change made, can use the .rowcount attribute of cursor object:

this read-only attribute specifies number of rows last .execute*() produced (for dql statements select ) or affected (for dml statements update or insert ).

after execute update statement, cursor.rowcount > 0 true if , if predicate(s) in where clause matched. implies update successful.

unrelated specific problem, recommend against using try-except shown in code example. better wrap 1 line , catch errors can handle. if intend calling scope handle error, catch in calling scope (or re-raise in function after doing necessary logging/housekeeping) rather suppressing , returning exception object.