Knowledge Base

PRB: CreateDynaset Err: Can't open any more tables or queries

Article ID: 113388

Article Last Modified on 10/30/2003

Microsoft Visual Basic 3.0 Professional Edition
Microsoft Visual Basic 3.0 Professional Edition

This article was previously published under Q113388

SYMPTOMS

After using the CreateDynaset method several times to create a dynaset from the dynaset itself, you will receive this error:

Can't open any more tables or queries.

Most often, you would be using the Sort or Filter property in this process. However, it is not necessary to do this to re-create the problem.

CAUSE

The number of times a dynaset can be created from itself is limited in the current design of Visual Basic.

WORKAROUND

To work around the problem, base all sorts or filters off of a different dynaset. The following example illustrates this:

Start a new project in Visual Basic. Form1 is created by default.
Add a command button (Command1) and a text box (Text1) to the form.

Add the following code in the command click event.

   Sub Command1_Click()
      Dim db As Database
      Dim ds As Dynaset
      Dim ds2 As Dynaset
      Set db = OpenDatabase("C:\VB\BIBLIO.MDB")
      Set ds = db.CreateDynaset("SELECT * FROM Authors")
      Set ds2 = ds
      Do
         iCount = iCount + 1
         Text1.Text = iCount
         ds2.Sort = "Author"
         Set ds = ds2.CreateDynaset()
      Loop
   End Sub

Run the program or press the F5 key.

The problem does not occur with snapshot objects.

STATUS

This behavior is by design in Visual Basic version 3.0 for Windows. However, Microsoft is considering a change for future releases.

MORE INFORMATION

Steps to Reproduce Problem

Start a new project in Visual Basic. Form1 is created by default.
Add a command button (Command1) and a text box (Text1) to the form.

Add the following code in the Command1 click event:

   Sub Command1_Click()
      Dim db As Database
      Dim ds As Dynaset
      Set db = OpenDatabase("C:\VB\BIBLIO.MDB")
      Set ds = db.CreateDynaset("SELECT * FROM Authors")
      Do
         iCount = iCount + 1
         Text1.Text = iCount
         Set ds = ds.CreateDynaset()
      Loop
   End Sub

Run the code. The error should occur on the tenth iteration.

Additional query words: 3.00

Keywords: kbprb KB113388