What's causing 'unable to connect to data source' for pyodbc?

Question

I'm trying to connect to an MSSQL database from python on Linux (SLES).

I have installed pyodbc and Free TDS. From the command line:

tsql -H server -p 1433 -U username -P password

Connects to the server without a problem, however, from Python:

import pyodbc
pyodbc.connect(driver='{FreeTDS}', server='server', database='database', uid='username', pwd='password')

Yields an error:

pyodbc.Error: ('08001', '[08001] [unixODBC][FreeTDS][SQL Server]Unable to connect to data source (0) (SQLDriverConnect)')

I'm finding this error unhelpfully vague. Even a suggestion to narrow down the issue would be helpful right now.

Edit: Looking at the TDS log dump it looks like this is where the whole thing falls apart:

token.c:328:tds_process_login_tokens()
util.c:331:tdserror(0x87bbeb8, 0x8861820, 20017, 115)
odbc.c:2270:msgno 20017 20003
util.c:361:tdserror: client library returned TDS_INT_CANCEL(2)
util.c:384:tdserror: returning TDS_INT_CANCEL(2)
util.c:156:Changed query state from IDLE to DEAD
token.c:337:looking for login token, got  0()
token.c:122:tds_process_default_tokens() marker is 0()
token.c:125:leaving tds_process_default_tokens() connection dead
login.c:466:login packet accepted
util.c:331:tdserror(0x87bbeb8, 0x8861820, 20002, 0)
odbc.c:2270:msgno 20002 20003
util.c:361:tdserror: client library returned TDS_INT_CANCEL(2)
util.c:384:tdserror: returning TDS_INT_CANCEL(2)
mem.c:615:tds_free_all_results()
error.c:412:odbc_errs_add: "Unable to connect to data source"

Answer 1

I try with:

• MS SQL 2008 Datacenter
• Ubuntu 12.04 TLS (amd64)
• Python 2.7

And this works for me:

Test connection:

tsql -H 10.19.4.42 -p 1433 -U DAVIDG -P 123456

on /etc/odbcinst.ini add:

[ODBC]
Trace = Yes
TraceFile = /tmp/odbc.log

[FreeTDS]
Description = TDS driver (Sybase/MS SQL)
Driver = /usr/lib/x86_64-linux-gnu/odbc/libtdsodbc.so
Setup =  /usr/lib/x86_64-linux-gnu/odbc/libtdsS.so
UsageCount = 1

on /etc/odbc.ini add:

[SQLDemo]
Description=my dsn
Driver=FreeTDS
Database=teste3
Servername=SQLDemo

on /etc/freetds/freetds.conf add:

[SQLDemo]
        host = 10.19.4.42
        port = 1433
        tds version = 8.0

test with test.py:

#!/usr/bin/python

import pyodbc
cnx = pyodbc.connect("DSN=SQLDemo;UID=DAVIDG;PWD=123456")

cursor = cnx.cursor()
cursor.execute("select * from Company;")
for row in cursor:
  print row.Name