FIX: Using ODBCDirect, Transactions and Oracle Causes Hang

• Microsoft Visual Basic Enterprise Edition for Windows, version 5.0

SYMPTOMS

When connecting to an Oracle database using DAO and ODBCDirect, the application hangs when an Insert statement is within a Begin/Commit Transaction and that procedure is called the second time.

CAUSE

This is caused by a known problem in the Microsoft ODBC Driver for Oracle, Msorcl10.dll, version 1.0.

RESOLUTION

To work around this problem the QueryTimeout property of the Connection object must be set to zero (0). Uncomment the following line of code to make the example run without error:

   Cn.QueryTimeout = 0 

STATUS

Microsoft has confirmed this to be a problem in the Microsoft ODBC Driver for Oracle, Msorcl10.dll. This issue has been resolved with the 2.0, or higher, version of the Microsoft Oracle ODBC Driver. This driver can be obtained in Visual Studio 5.0 and higher, MDAC 1.5 or higher, and the Data Access Software Development Kit (SDK).

MORE INFORMATION

Steps to Reproduce Behavior

1. Create a Standard EXE project with two Command Buttons on the new Form.



2. Add this code to the General Declarations Section:

   
         Option Explicit
         Dim Ws As Workspace
         Dim Cn As Connection
         '
         ' Note that the parameters in the connection string must be changed
         ' to match your configration.
   
         Private Sub Command1_Click()
            On Error Resume Next
            MousePointer = vbHourglass
            Cn.Execute "DROP TABLE CODETEST"
            Cn.Execute "CREATE TABLE CODETEST(CODE VARCHAR2(10) NULL)"
            MousePointer = vbNormal
            MsgBox "Table Created"
         End Sub
   
         Private Sub Command2_Click()
         Dim strSQL As String
         Dim Qd As QueryDef
         Dim txtValue As String
   
         txtValue = "abc"
            Ws.BeginTrans
   
            strSQL = "insert into codetest (code) values ('" & txtValue & "')"
            Set Qd = Cn.CreateQueryDef("", strSQL)
            Qd.Execute  'Fails here the second time
            If (Err.Number <> 0) Then
                MsgBox ("[cmdExecute_Click] - " + Err.Description)
            Else
                Qd.Close
            End If
   
           Ws.CommitTrans
   
         MsgBox "Click me again and I will crash"
   
         End Sub
   
         Private Sub Form_Load()
         Dim strConn As String
            Command1.Caption = "Create Table"
            Command2.Caption = "Enter Data"
   
            'Replace <data source name>, <user ID>, and <password> with the
            'DSN, user ID, and password for your Oracle system.
   
            strConn = "odbc;dsn=<data source name>; _
            uid=<user ID>;pwd=<password>"
            Set Ws = CreateWorkspace("", "admin", "", dbUseODBC)
            Set Cn = Ws.OpenConnection("", dbDriverNoPrompt, False, strConn)
   
           'Cn.QueryTimeout = 0 ' This is the workaround line of code
   
         End Sub
   
         Private Sub Form_Unload(Cancel As Integer)
            Cn.Close
            Ws.Close
         End Sub
    




3. Change the <data source name>, <user ID>, and <password> in the connect string (strConn) to the DSN, user ID, and password for your Oracle system.



4. Save the Project.



5. Run the Project by pressing F5.



6. Click on the Create Table button (The user database may have to be changed in the code to match your setup).



7. Click on the Enter Data button. The first time one record is inserted. Clicking on the "Enter Data" button the second time will hang the application. Go into the Task Manager (CNTL, ALT, DELETE) to Exit the app.

Additional query words: kbODBC kbOracle kbDatabase kbDriver kbVB kbDAO

Keywords : kbDriver kbODBC kbVS kbODBC200fix kbGrpVBDB kbGrpMDAC VBKBAutomation VBKBRemote
Version : WINDOWS:5.0
Platform : WINDOWS
Issue type : kbbug