ACC2000: Error Using CurrentProject.Connection in Transactions

If you use the CommitTrans or RollbackTrans methods directly with the CurrentProject.Connection object, you may receive one of the following errors:

Each time the CurrentProject.Connection object is used, it has a different pointer to the connection. In effect, the instance or pointer to that object is temporary. This is why you see no error on CurrentProject.Connection.BeginTrans, but you do receive an error once you try to commit or rollback the transaction.

Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements. CAUTION: If you follow the steps in this example, you modify the sample database Northwind.mdb. You may want to back up the Northwind.mdb file and follow these steps on a copy of the database.

Set an object variable once to CurrentProject.Connection and use it for your transaction processing, such as in the following example. Here, "c" is the Connection object used for transactions:

NOTE: The sample code in this article uses Microsoft ActiveX Data Objects. For this code to run properly, you must reference the Microsoft ActiveX Data Objects 2.x Library (where 2.x is 2.1 or later.) To do so, click References on the Tools menu in the Visual Basic Editor, and make sure that the Microsoft ActiveX Data Objects 2.x Library check box is selected.

1. Open the sample database Northwind.mdb.
2. In the Database windows, click Modules under Objects, and then click New.
3. Type the following code in the new module:

   Sub tstConnectionObj()
   
      Dim c As ADODB.Connection
      Dim rs As ADODB.Recordset
   
      Set c = CurrentProject.Connection
      Set rs = New ADODB.Recordset
   
      rs.Open "Categories", c, adOpenDynamic, adLockOptimistic
   
      c.BeginTrans
      rs.Fields(1) = "Drinks"
   
      rs.Update
      MsgBox "Updated field to " & rs.Fields(1) & "."
   
      c.RollbackTrans
      rs.Requery
      MsgBox "Rolled back field to " & rs.Fields(1) & "."
   
   End Sub
   					

4. In the Immediate window, type the following and press ENTER:

   tstConnectionObj
   						

   Note that you see the following message:
   Updated field to Drinks.
5. Click OK on the message. Note that you see the following message:
   Rolled back field to Beverages.
6. Click OK on the message.

Steps to Reproduce Behavior

1. Open the sample database Northwind.mdb.
2. In the Database windows, click Modules under Objects, and then click New.
3. Type the following code in the new module:

   Sub tstCurrentProj()
   
      Dim rs As ADODB.Recordset
   
      Set rs = New ADODB.Recordset
   
      rs.Open "Categories", CurrentProject.Connection, adOpenDynamic, _
        adLockOptimistic
   
      CurrentProject.Connection.BeginTrans
      rs.Fields(1) = "Drinks"
      rs.Update
      MsgBox "Updated field to " & rs.Fields(1) & "."
   
      CurrentProject.Connection.RollbackTrans
      MsgBox "Rolled back field to " & rs.Fields(1) & ".
   
   End Sub
   					

4. In the Immediate window, type the following and press ENTER:

   tstCurrentProj
   						

   Note that you see the following message:
   Updated field to Drinks.
5. Click OK on the message.
   
   Note that you see the first error message mentioned in the "Symptoms" section of this article.