Teradata ODBC 驱动程序不能通过 Python 连接，但可以通过 VBA 连接

Question

I have a strange problem where i am able to connect to Teradata using VBA but not able to connect via python from same teradata driver.

Below is the code snippet:

1) VBA

connection_string = "Driver={Teradata};" & "DBCName=" & dsn_name & ";Database=" & database_name & "; User ID =" & user_name & ";Password=" & password

and i am able to connect to teradata successfully.

2) Python

import pyodbc
dsn_name="td_dev"
user_name="test"
password="test"
db = pyodbc.connect('DSN=' + dsn_name + ';UID='+ user_name +';PWD=' + password + ';')

this statement throws me below error-

('IM003', '[IM003] Specified driver could not be loaded due to system error  126
: The specified module could not be found. (Teradata, C:\\Program Files (x86)\\T
eradata\\Client\\13.10\\ODBC Driver for Teradata\\Lib\\tdata32.dll). (160) (SQLD
riverConnect)')

I have tried various methods like : Re-Installing TD drivers, setting up the environment variables.

But the question remains, how i am able to connect via excel VBA but not python.

Answer 1

I think you need to add the driver argument. It is possible that you have multiple teradata drivers. If that is the case you need to explicitly declare which driver to be used: Eg

#To get a list of drivers
import pyodbc
pyodbc.drivers()

That will return a list of odbc drivers in your system. Output eg

['SQL Server',
 'SQL Server Native Client 10.0',
 'Amazon Redshift (x64)',
 'Microsoft Access Driver (*.mdb, *.accdb)',
 'Microsoft Excel Driver (*.xls, *.xlsx, *.xlsm, *.xlsb)',
 'Microsoft Access dBASE Driver (*.dbf, *.ndx, *.mdx)',
 'Microsoft Access Text Driver (*.txt, *.csv)',
 'Teradata',
 'SQL Server Native Client 11.0',
 'PostgreSQL ANSI(x64)',
 'PostgreSQL Unicode(x64)',
 'MySQL ODBC 5.3 ANSI Driver',
 'MySQL ODBC 5.3 Unicode Driver',
 'Teradata Database ODBC Driver 16.10',
 'Teradata 7.1 DB2 Wire Protocol',
 'Teradata 7.1 Oracle',
 'Teradata 7.1 Oracle Wire Protocol',
 'Teradata 7.1 SQL Server Legacy Wire Protocol',
 'Teradata 7.1 SQL Server Wire Protocol',
 'Teradata 7.1 MySQL Wire Protocol',
 'Teradata 7.1 PostgreSQL Wire Protocol']

Since there is both Teradata and Teradata Database ODBC Driver 16.10. We need to declare which one to be used:

host, username, password = 'hostname','UserName', 'Password'
tdConnect = pyodbc.connect('Driver=Teradata Database ODBC Driver 16.10;DBCNAME=%s;DSN=XXXX;UID=%s;PWD=%s'%(host, username, password),autocommit=True)

I hope that fixed your issue.

Answer 2

In my case, I was able to fix this by following "Workaround" as described in https://knowledge.informatica.com/s/article/134879 , even though I'm not using Informatica nor Teradata 13.

The workaround that solved my problem, "system error 126", which I was getting using Python, pyodbc, and Teradata ODBC drivers 14.10.00:

Copy all files in C:\\Program Files\\Teradata\\Client\\14.10\\Shared ICU Libraries for Teradata\\lib to the folder, C:\\Program Files\\Teradata\\Client\\14.10\\ODBC Driver for Teradata nt-x8664\\Lib

No reboot was required. The next time I ran my python code, it successfully connected to Teradata via ODBC.

The fact that both Excel and the Teradata ODBC test utility, C:\\Program Files\\Teradata\\Client\\14.10\\ODBC Driver for Teradata nt-x8664\\Bin\\tdxodbc.exe were able to make ODBC connections BEFORE I made this change is weird. It tells me that pyodbc uses a different mechanism to resolve ODBC DLL dependencies than both Excel and Teradata's ODBC test utilty. It's probably something to do with what's in the PATH variable as modified by Teradata's installer.