I'm not sure I understand optimistic locking. The only way I can see
it working is if the client can send a message to the DBMS saying "I
want to update table-row-cell xyz to a new value y if the current
value is still x otherwise abort and return error."
On Nov 15, 2:55 am, Jamie Fraser <jamie.fra...@gmail.com> wrote:
> If you are using TableAdapters/DataSets, pretty much all of that is handled
> for you automatically.
>
> Concurrency is also handled, depending on the options you specified when you
> created the TableAdapters - optimistic concurrency is generally best for
> everything as it avoids locking.
>
> On Thu, Nov 4, 2010 at 2:49 PM, Davej <galt...@hotmail.com> wrote:
> > I'm looking for a basic outline of the steps that are usually used in
> > a multi-user database app. So far I've only played with the single-
> > user situation, so when I load the form I load the form's datagrid...
>
> > Try
> > Me.TblMy_TableTableAdapter.Fill(Me.My_DBDataSet.tblMy_Table)
> > Catch ex As Exception
> > MsgBox("Database Error: " & ex.Message)
> > End Try
>
> > And then when the user exits the form I simply save...
>
> > Try
> > Me.Validate()
> > Me.TblMy_TableBindingSource.EndEdit()
> > If Me.My_DBDataSet.HasChanges = True Then
> > If MsgBox("Post Edits to Remote Database?", MsgBoxStyle.YesNo,
> > _
> > "UPDATES PENDING") = MsgBoxResult.Yes Then
> > Me.TableAdapterManager.UpdateAll(Me.My_DBDataSet) ' update
> > remote database
> > End If
> > End If
> > Catch ex As Exception
> > MsgBox("Database Error: " & ex.Message)
> > End Try
> > Me.Close()
>
> > Now what is the outline of the save operation for a simple non-
> > cascading multi-user situation? I'm thinking you probably want/need to
> > identify your updates, inserts and deletes and then go through some
> > sort of read-lock-write-unlock loops? I have no idea. I have no
> > exposure to this more complex stuff at all.
>
> > Thanks,
>
> > Dave
