Legacy VB6 application under Win7 SQL error
- by Shial
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.
