Dim oRec As New cRecordset Dim oDAL As New cDAL ' Assume local DAL so don't need serialization Set oRec = oDAL.OpenRecordset("Employees") oRec.Edit oRec.Fields("FirstName") = "Adam Magee" oRec.Update oDAL.UpdateRecordset oRec
Synchronizing a Recordset
After a cRecordset object has been used by UpdateRecordset to successfully update the data source, the cRecordset object needs to have the same changes committed to itself, which is accomplished by means of the Synchronize method.
Using the Synchronize method will remove all Deleted rows from the recordset and will set any Updated or Created rows to Read status. This gives the developer using the cRecordset object control over committing changes and also means the recordset state can be maintained in the event of an UpdateRecordset failure. Here is an example of synchronizing a recordset after a row has been updated:
oDAL.UpdateRecordset oRec oRec.Synchronize Parameters
Simply supplying the name of a cRecordset object to OpenRecordset is usually not enough information, except maybe when retrieving entire sets of data, so we need a way of supplying parameters to a DAL cRecordset operation.
This is achieved by using a cParams object. The cParams object is simply a collection of cParam objects, which have a name and a value. The cParams object, like the cRecordset object, can also be serialized. This is useful if the parameters need to be maintained on another machine.
|Add||Adds a new cParam object with a name and a value|
|Item||Returns a cParam object|
|Count||Returns the count of collected cParam objects|
|Remove||Removes a cParam object|
|Serialize||Converts or sets the content of cParams object into an array|
|Name||Name of the parameter|
|Value||Variant value of the parameter|
Here is an example of retrieving a recordset with parameters:
Dim oDAL As New cDAL Dim oRec As New cRecordset Dim oPar As New cParams oPar.AddField "EmpID", "673" oPar.AddField "CurrentlyEmployed", "Yes" Set oRec = oDAL.OpenRecordset("Employees", oPar) MsgBox oRec.RecordCount
We can see now that only two well-defined objects are parameters to the DAL-cRecordset and cParams-and both of these objects support serialization, giving a consistent, distributed operation-aware interface.