[python-win32] Recovering from AODB Exceptions, possible?

[Rex Corrovan]

Actually, I do have a lot more exception handling going on. I just tried to 
keep the code simple to demonstrate the problem. But yeah, if I except in a 
way I am not expecting (ie: anything but a record exists) I handle it 
differently.

Thanks for the tips though, and most definatly for making sure I am using 
good practices :)

Rex


From: "Mark Hammond" <mhammond at skippinet.com.au>
To: "'Rex Corrovan'" <rex555 at hotmail.com>,<python-win32 at python.org>
Subject: RE: [python-win32] Recovering from AODB Exceptions, possible?
Date: Sat, 10 Feb 2007 18:04:19 +1100

 > So I have a function that ries to add a record:
 >
 >     def EntryAdd(self, dataDict):
 >         try:
 >             self._DBConn.MoveFirst()
 >             self._DBConn.AddNew()
 >             for key, value in dataDict.items():
 >                 self._DBConn.Fields.Item(key).Value = value
 >             self._DBConn.Update()
 >         except pywintypes.com_error, e:
 >             print e
 >             print 'error text here'
 >         return True
 >
 > So if the error already exists I get an exception, no
 > problem, I handle and
 > log it.

In general, you should try and be specific about handling exceptions.
Assuming you want to only handle "record exists" type exceptions, you should
probably write something closer to:

      def EntryAdd(self, dataDict):
          self._DBConn.MoveFirst()
          self._DBConn.AddNew()
          for key, value in dataDict.items():
             self._DBConn.Fields.Item(key).Value = value
          try:
              self._DBConn.Update()
          except pywintypes.com_error, e:
              hr, msg, exc = e
              if hr != SOME_CONSTANT_MEANING_RECORD_EXISTS:
                  raise
              print e
              print 'record exists'
          return True

I'm not sure what SOME_CONSTANT_MEANING_RECORD_EXISTS is, and it may even be
necessary to unpacl 'exc' to get a reliable error code.  All other errors
will still result in an uncaught exception - so any other errors you have
are not silently handled as if they were the common "record exists".  You
probably still want an outer exception handler that handles all errors in a
sane way

Mark

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