When I talk about how database interactions work, I usually use analogies to how instrument control works. If you have an instrument and use the VISA Write to send a string to the device, the Write returns no error if the command string was correctly written to the instrument. The actual command might be completely wrong for that instrument, but the VISA function did transfer the information correctly. The same works for the SQL Execute VI. As long as the SQL statement uses the correct syntax, the Execute returns without an error. However, that doesn't mean the SQL statement performed the operation you wanted it to.
If you want to verify the information, do a query of the same record you just updated and compare the values. If they are different, the operation didn't complete correctly.
Also, if you aren't already doing so, I highly recommend using the drivers from Oracle rather than the ones written by Microsoft for Oracle. The MS drivers don't contain as much error checking or as many features as the Oracle ones do.
