Database connections on 64-bit systems

Hello everyone,

If you’re running a x64 variant of Windows, you might bump into the following problem whilst developing programs that work with databases:

You can’t seem to establish a connection to the database.

This usually means that there aren’ t 64-bit drivers available for the database engine you’re using (For example, MS Access)

The solution for your problem is easy:

• If you are developing a .NET application in Visual Studio:
  • For Visual Basic projects, go to the Compile tab and press the Advanced Compile Options button.
    In the dialog change the Target CPU to x86
  • For Visual C# projects, go to the Build tab and change Platform Target to x86
• If you are developing a Java application and you’re using DSN:
  • Add a System DSN using the odbcad32.exe located in C:\Windows\SysWOW64\odbcad32.exe and NOT the one located in C:\Windows\System32\odbcad32.exe (The one that opens when you go to Control Panel > Administrative Tools > Data Sources (ODBC))

For some database engines (such as SQL Server) there are 64-bit drivers available (and usually automaticly installed).
Therefor you can develop 64-bit applications for SQL Server, but most other database engines only work with 32-bit drivers.

That’s pretty much the basic solution to the problem.

If you have any questions, please ask them and I’ll do my best to help you 🙂

– Dirk

P.S.: Incase you’re wondering how you have to work with DSN files in .NET, here is a small code snippet to establish a connection using a System DSN with ODBC:

Dim oCon As New System.Data.Odbc.OdbcConnection("DSN=myDSN")