[ExtensionOf(formDataSourceStr(RouteInventProd, ProdRouteTable))]
final class RouteInventProd_ProdRouteTable_ds_Write_Ext
{
    public void write()
    {
        ProdRouteTable prod = this.cursor();
        RouteInventProdTmp tmp = this.formRun()
            .dataSource(formDataSourceStr(RouteInventProd, RouteInventProdTmp))
            .cursor();

        if (tmp) prod.MyNewField = tmp.MyNewField;

        next write(); // framework persists update/insert correctly
        this.reread(); // optional        this.reread(); // optional
    }