I'm using the following code to work out the next unique Order Number in an access database. ServerDB is a "System.Data.OleDb.OleDbConnection"
Dim command As New OleDb.OleDbCommand("", serverDB)
command.CommandText = "SELECT max (ORDERNO) FROM WORKORDR"
iOrder = command.ExecuteScalar()
NewOrderNo = (iOrder + 1)
If I subsequently create a WORKORDR (using a different DB connection), the code will not pick up the new "next order number."
e.g.
iFoo = NewOrderNo
CreateNewWorkOrderWithNumber(iFoo)
iFoo2 = NewOrderNo
will return the same value to both iFoo and iFoo2.
If I Close and then reopen serverDB, as part of the "NewOrderNo" function, then it works. iFoo and iFoo2 will be correct.
Is there any way to force a "System.Data.OleDb.OleDbConnection" to refresh the database in this situation without closing and reopening the connection. e.g. Is there anything equivalent to serverdb.refresh or serverdb.FlushCache
How I create the order. I wondered if this could be caused by not updating my transactions after creating the order. I'm using an XSD for the order creation, and the code I use to create the record is ...
Sub CreateNewWorkOrderWithNumber(ByVal iNewOrder As Integer)
Dim OrderDS As New CNC
Dim OrderAdapter As New CNCTableAdapters.WORKORDRTableAdapter
Dim NewWorkOrder As CNC.WORKORDRRow = OrderDS.WORKORDR.NewWORKORDRRow
NewWorkOrder.ORDERNO = iNewOrder
NewWorkOrder.name = "lots of fields filled in here."
OrderDS.WORKORDR.AddWORKORDRRow(NewWorkOrder)
OrderAdapter.Update(NewWorkOrder)
OrderDS.AcceptChanges()
End Sub
From MSDN
Microsoft Jet has a read-cache that is updated every PageTimeout milliseconds (default is 5000ms = 5 seconds). It also has a lazy-write mechanism that operates on a separate thread to main processing and thus writes changes to disk asynchronously. These two mechanisms help boost performance, but in certain situations that require high concurrency, they may create problems.