INF: Running ODBC Applications as Windows NT Services

PSS ID Number: Q136481

Article Last Modified on 06-11-2000

• Microsoft Open Database Connectivity 2.5

Summary

ODBC applications running as Windows NT services may encounter the following error when attempting to connect to an ODBC data source:

szSqlState = "IM002"
pfNativeError = 0
szErrorMsg = "[Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified"

More Information

When a standard ODBC data source is defined, it is specific to the Windows NT account under which the ODBC Administrator process is running. This is because the data source definition is stored in the HKEY_CURRENT_USER hive in the Windows NT registry. Applications running in environments which do not have that specific user's hive set up as HKEY_CURRENT_USER will not have access to that data source.

Applications running as Windows NT services can be made to run under a Windows NT account using the control panel, but may be running at times when that user's hive is not the one set up as HKEY_CURRENT_USER. For example, if the NT account is not logged on, their hive will not be set as HKEY_CURRENT_USER, and the NT service will not be able to access the ODBC data source. This also applies to DLLs running as SQL Server version 6.0 Extended Stored Procedures because they run as part of the SQL Server process, which always runs as a Windows NT service. This same problem also affects applications running under the Windows NT Scheduler service, which covers applications started with the Windows NT AT command.

Microsoft ODBC version 2.5 addresses this problem by introducing the concept of a system data source. The definitions of system data sources are stored in the registry HKEY_LOCAL_MACHINE hive under SOFTWARE/ODBC/ODBC.INI where they will always be accessible to Windows NT services.

ODBC 2.5 started shipping with Microsoft SQL Server version 6.0 and Microsoft Office 95, and will ship with future releases of other ODBC- capable products.

Users who do not already have an ODBC 2.5 driver installed can obtain the ODBC 2.5 ODBC Administrator and Driver Manager by downloading the file ODBC25.exe from the Microsoft Software Library (MSL).

The following file is available for download from the Microsoft Software Library: