User Defined Table locked when multi users try to save data?

Question

Hi All,
I am having a problem with User Define Table (UDT). I am just checking if somebody having the same problem as mine (any patch level).
I've developed an add-on to save additional data to some UDTs upon saving a Production Order. I added my code in FormDataEvent (After Action = True and ActionSuccess = True).
Here are my sequences to save the data:
1. Start Transaction
2. Remove Existing Data from 3 UDTs linked to the production order number.
3. Save to table 1, using UserTable object
4. Call function A to save to table2 , using UserTable object
5. Call function B to save to table 3, using UserTable object
6. Commit Transaction.
Note: I have a try catch and rollback the transaction if any exception thrown by .NET and SAP. Below are parts of my coding to handle exception from SAP
                If oUserTable.Add() <> 0 Then
                    oCompany.GetLastError(ErrCode, ErrMsg)
                    Throw New ApplicationException(ErrCode & "-" & ErrMsg)
                End If
in the try catch block, i add the following code
            If oCompany.InTransaction Then
                oCompany.EndTransaction(SAPbobsCOM.BoWfTransOpt.wf_RollBack)
                SBO_Application.MessageBox("[SaveRoute]:" & ex.Message)
                Return False
            End If
Now, the issue is in some occasions, when multi users try to save the Production Order, the data get deleted from the UDTs, but some of the data did not get saved yet it did not throw an exception. From our observation, it only happens when multi users are trying to save to the same table.
Does anybody having the same or similar issue? Really appreciate if you can share on this.
Many Thanks,
Harianto Ng

Answer 1

I Believe you should look carefully where in your code writting, you should start transaction and be sure of using end.transaction commit if the insert sends a succesfull message, and rollback it for negative message.
I used to start transacción right before .add method
Wha DBMS are u using?
Hope it helps.