pyodbc problem

Tue Jul 27 14:02:37 EDT 2010

I have a small problem: I can't get pyodbc to connect to a PostgreSQL 
database. All it does is spit out a malformed error message. When I run 
this:
==============================================
import pyodbc
dsn = pyodbc.dataSources()
print "Data sources: %s" % dsn
conn = pyodbc.connect(dsn="marchive")
print "ODBC connection: %s" % conn
==============================================
I get this:
==============================================
[kiwi at zappa python]$ python dsncheck.py
Data sources: {'ma': 'PostgreSQL', 'marchive': 'PostgreSQL'}
Traceback (most recent call last):
 File "dsncheck.py", line 6, in <module>
 conn = pyodbc.connect(dsn="marchive")
pyodbc.Error: ('0', '[0] [unixODBC]c (0) (SQLDriverConnectW)')
==============================================
so the data source exists and is evidently found by connect(), whiuch 
seems unable to make sense of it.
The pgsql module works well, but I would prefer to use ODBC because its 
not so closely bound to a single RDBMS. unixODBC, which I understand 
underlies pyodbc, works OK too:
==============================================
[kiwi at zappa python]$ isql marchive marchive n/a
+---------------------------------------+
| Connected! |
| |
| sql-statement |
| help [tablename] |
| quit |
| |
+---------------------------------------+
SQL> select count(*) from address;
+---------------------+
| count |
+---------------------+
| 32 |
+---------------------+
SQLRowCount returns 1
1 rows fetched
SQL> quit
==============================================
Questions:
- Why does pyodbc blow up when its apparently trying to talk to unixODBC?
- What does this mean:
 pyodbc.Error: ('0', '[0] [unixODBC]c (0) (SQLDriverConnectW)')
I'm new to Python, though not to Linux, PostgreSQL, ODBC, C or Java. 
My rig and software:
Linux: 	 Fedora 12 Where I'm running Python and ODBC,
		 Lenovo Thinkpad R61i: Core Duo.
 Fedora 10 Where PostgreSQL is installed,
 IBM NetVista: Pentium III. 
PostgreSQL: 8.3.8
Python: 2.6.2
pyodbc 2.1.5-3.fc12 ) By yum from RH repository
unixODBC 2.2.14-11.fc12 )
-- 
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |