thnx "SAKryukov"
i got my solution.
it was this=========
Set cn = New ADODB.Connection
Set rec = New ADODB.Recordset
cn.Open "provider=MSDAORA.1; user id = scott; password=tiger;"
Set rec = New ADODB.Recordset
rec.ActiveConnection = cn
rec.LockType = adLockOptimistic
rec.CursorLocation = adUseClient
rec.Source = "blood_stock"
rec.Open "select * from blood_stock"
rec.Fields(1) = rec.Fields(1) + Combo1.Text
rec.Update
""fields(1) which i want to update and combo1 from where i fetch the value.""