Assigning different Exception message

[Tor Erik Soenvisen]

try:
self.cursor.execute(sql)
except AttributeError, e:
if e.message == "oracleDB instance has no attribute 'cursor'":
e.message = 'oracleDB.open() must be called before' + \
' oracleDB.query()'
raise AttributeError, e

This code does not re-assign e's message when the conditional is satisfied.
Why not?

regards

[Peter Otten]

Tor Erik Soenvisen wrote:

try:
self.cursor.execute(sql)
except AttributeError, e:
if e.message == "oracleDB instance has no attribute 'cursor'":
e.message = 'oracleDB.open() must be called before' + \
' oracleDB.query()'
raise AttributeError, e

This code does not re-assign e's message when the conditional is
satisfied. Why not?

It does, but e.args is used to generate the message shown:

>>try:

.... None.not_there
.... except AttributeError, e:
.... e.args = ("whatever",)
.... raise e
....
Traceback (most recent call last):
File "<stdin>", line 5, in <module>
AttributeError: whatever

However, I would prefer to rewrite your snippet along the lines:

try:
cursor = self.cursor
except AttributeError:
raise EriksCustomError("oracleDB.open()...")
else:
cursor.execute(sql)

Peter