BUG: ODBC Getchunk Method on Non-Memo Field Causes GPF/UAE (97082)


The information in this article applies to:

  • Microsoft Visual Basic Professional Edition for Windows 2.0
This article was previously published under Q97082

SYMPTOMS

Attempting to use the GetChunk method on a Text field or any field that has a data type other than Memo results in an unrecoverable application error (UAE) or a general protection (GP) fault.

CAUSE

The GetChunk method returns a string that represents all or a portion of a Memo field and only a Memo field in a specified dynaset.

WORKAROUND

To avoid the problem, use code to ensure that the field is a Memo field before you call the GetChunk method. For example, replace the following line shown in step 2 of the More Information section of this article: 
   string1$ = ds(ds.Fields(NonMemoFieldNum%).Name).GetChunk(0, 50)
with this code: 
   If ds.Fields(NonMemoFieldNum%).type = 12 Then
      string1$ = ds(ds.Fields(NonMemoFieldNum%).Name).GetChunk(0, 50)
   End If

STATUS

Microsoft has confirmed this to be a bug in the Professional Edition of Microsoft Visual Basic version 2.0 for Windows. We are researching this problem and will post new information here in the Microsoft Knowledge base as it becomes available.

MORE INFORMATION

Steps to Reproduce Problem

  1. Start the Professional Edition of VB.EXE with ODBC support already installed.
  2. Add the following code to the Form_Click event procedure of Form1: 
       Form_Click ()
      Dim db As database
      Dim ds As dynaset

      ServerName$ = "aServerName"  ' Provide the name of a real server.
      DBName$ = "aDatabase"        ' Name of a database on the server.
      TableName$ = "aTable"        ' Name of a table in the database.
      UserName$ = "aUser"          ' login id
      PW$ = ""                     ' password
      NonMemoFieldNum% = 1  ' This could be any field in the table that
                            '  is not of type "Memo".

      'Connect to the SQL database
      Connect$ = "UID=" + UserName$ + ";PWD=" + PW$ + ";DBQ=" + DBName$

      Set db = OpenDatabase(ServerName$, False, False, Connect$)

      Set ds = db.CreateDynaset(TableName$)
      ' GP fault occurs on the following line:
      string1$ = ds(ds.Fields(NonMemoFieldNum%).Name).GetChunk(0, 50)
   End Sub
  3. Press the F5 key or ALT+R+S, and click Form1.
This results in a GP fault usually at address 0009:08EC in VBODBCA.DLL.
Modification Type:MinorLast Reviewed:1/9/2003
Keywords:kbbug KB97082
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