Sql-server – Legacy VB6 application under Win7 SQL error

sql servervb6windows 7

We have a rather unfortunate legacy application at work, written originally in VB6 it predates anybody in our IT department by at least 5 years. We have a contracted developer for ongoing maintenance and where he can he rewrites sections over into .NET code (Not sure about his techniques here, this is a side job for his regular work as an IBM engineer) the application works fine (such as it is) under windows XP. We have only a couple of Windows 7 machines mainly for testing and this application seems to run into a wall. Things like the background not loading and SQL errors. This is even running under administrator.

Running an SQL trace from the ODBC control panel shows several interesting things. It makes a connection to the database successfully initially where it runs a query to determine if it is running the correct version. This query works fine. 

            558-1af0 ENTER SQLExecDirectW 
  HSTMT               0x020D7548
  WCHAR *             0x04C8F0F0 [     115] "SELECT count(*) c FROM tblSoftwareVersion WHERE  fldSoftwareVersion = '123456' AND fldSoftwareName = 'Application.VB'"
  SDWORD                   115

BMS             558-1af0 EXIT  SQLExecDirectW  with return code 1 (SQL_SUCCESS_WITH_INFO)
  HSTMT               0x020D7548
  WCHAR *             0x04C8F0F0 [     115] "SELECT count(*) c FROM tblSoftwareVersion WHERE  fldSoftwareVersion = '123456' AND fldSoftwareName = 'Application.VB'"
  SDWORD                   115

It then seems to drop its connection and can't find the ODBC connection despite the fact its connecting to the same DB. From the trace it looks like it configures the connection then it starts firing off SQLFreeStmt to unbind and close out then when in the application and it tries to do its thing there is no connection.

558-1af0 ENTER SQLFreeStmt 
  HSTMT               0x020D7548
  UWORD                        2 <SQL_UNBIND>

BMS             558-1af0 EXIT  SQLFreeStmt  with return code 0 (SQL_SUCCESS)
  HSTMT               0x020D7548
  UWORD                        2 <SQL_UNBIND>

Then this happens when I try to do something that pulls data

            558-1af0 ENTER SQLDriverConnectW 
  HDBC                0x020DDA00
  HWND                0x00000000
  WCHAR *             0x73EF8634 [      -3] "******\ 0"
  SWORD                       -3 
  WCHAR *             0x73EF8634 
  SWORD                       -3 
  SWORD *             0x00000000
  UWORD                        0 <SQL_DRIVER_NOPROMPT>

BMS             558-1af0 EXIT  SQLDriverConnectW  with return code -1 (SQL_ERROR)
  HDBC                0x020DDA00
  HWND                0x00000000
  WCHAR *             0x73EF8634 [      -3] "******\ 0"
  SWORD                       -3 
  WCHAR *             0x73EF8634 
  SWORD                       -3 
  SWORD *             0x00000000
  UWORD                        0 <SQL_DRIVER_NOPROMPT>

  DIAG [IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified (0)

Nearly all of my searching on this issue comes up with programming issues where the connection string has a problem. The only thing that is different in this particular scenario though is Windows 7, I know the connection string is fine since it works on the XP machines. The VB components are supposed to be still functional under Win7. My computer is running 32 bit win7 and my VP is running Win7 64 bit and both have the same problem so that can be ruled out.

I have already tried reinstalling the SQL Native Client and the VB runtime as well as the application in question. Hopefully I can find a solution and not have to resort to using the XP VM.

Edit – Well after many attempts we have been forced to go with the XP VM as the solution here. Either the VB compnents aren't as compatible as they claim or this ancient app is doing something funny.

Best Answer

If it's an application that runs from the desktop (i.e. not as a service) did you try setting the application to run in compatibility mode? I had a similar problem with a VB6 program (same function to read the registry called from two different parts of the program, one works, the other does not, but from the VB6 IDE both work) and just right-clicking and having Win7 test for compatibility and choose XP SP2 mode cured the problem.

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