Getting error condition from MySQLdb

[Derek Fountain]

I was trying to use MySQLdb to connect to a database. All is OK, except I
can't figure out how to get the details of an error. Suppose I try to
connect to a non existant server, or with the wrong password - how do I get
a meaningful error message which I can present to my user?

[Andy Todd]

Re: Getting error condition from MySQLdb

Derek Fountain wrote:
[color=blue]
> I was trying to use MySQLdb to connect to a database. All is OK, except I
> can't figure out how to get the details of an error. Suppose I try to
> connect to a non existant server, or with the wrong password - how do I get
> a meaningful error message which I can present to my user?
>[/color]

In Python whenever an error occurs an exception is raised. I'd suggest a
quick read of the section of the tutorial that explains this;

http://www.python.org/doc/current/tut/node10.html

Then fire up a Python command prompt and try some things out. For
instance, on my Windows machine if I try;
[color=blue][color=green][color=darkred]
>>> import MySQLdb
>>> mydb=MySQLdb.co nnect(db='wibbl e')[/color][/color][/color]

I get a nice traceback;

Traceback (most recent call last):
File "<input>", line 1, in ?
File "C:\PROGRA~2\PY THON23\Lib\site-packages\MySQLd b\__init__.py",
line 63, in Connect
return apply(Connectio n, args, kwargs)
File "C:\PROGRA~2\PY THON23\Lib\site-packages\MySQLd b\connections.p y",
line 115, in __init__
self._make_conn ection(args, kwargs2)
File "C:\PROGRA~2\PY THON23\Lib\site-packages\MySQLd b\connections.p y",
line 41, in _make_connectio n
apply(super(Con nectionBase, self).__init__, args, kwargs)
OperationalErro r: (2003, "Can't connect to MySQL server on 'localhost'
(10061)")

If I actually start up MySQL, I get;

Traceback (most recent call last):
File "<input>", line 1, in ?
File "C:\PROGRA~2\PY THON23\Lib\site-packages\MySQLd b\__init__.py",
line 63, in Connect
return apply(Connectio n, args, kwargs)
File "C:\PROGRA~2\PY THON23\Lib\site-packages\MySQLd b\connections.p y",
line 115, in __init__
self._make_conn ection(args, kwargs2)
File "C:\PROGRA~2\PY THON23\Lib\site-packages\MySQLd b\connections.p y",
line 41, in _make_connectio n
apply(super(Con nectionBase, self).__init__, args, kwargs)
OperationalErro r: (1049, "Unknown database 'wibble'")

Note that MySQLdb, like the majority of distributed modules, defines its
own exceptions. MySQLdb, to the best of my knowledge, implements the
standard DB-API exceptions. They are detailed here;

http://www.python.org/topics/database/DatabaseAPI-2.0.html

Regards,
Andy
--
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From the desk of Andrew J Todd esq - http://www.halfcooked.com/