RDO to ADO.NET

The RDO data access model can be mapped to .NET using 2 different methodologies, the behavior of this particular option is described as follows:

  • RDO connecting to SQLserver: This solution generates helper-free source code, however, there are many functional details that require manual implementation. We recommend using the next option since most of the lost functionality is implemented into the helper classes.
  • RDO connecting to any other provider: when ADO is used to connect to any other data provider besides SQLserver (Jet, ODBC,...) this option CANNOT be used. The next option must be compulsory used.

The member transformation for this data access technology is described as follows:

Class Maps To
RDO.rdoConnection System.Data.SqlClient.SqlConnection
RDO.rdoResultset System.Data.DataSet
RDO.rdoColumns The property “rdoColumns.item” is the only supported member of this class.
RDO.rdoError System.Data.SqlClient.SqlError
RDO.Parameter System.Data.SqlClient.SqlParameter
RDO.Parameters System.Data.SqlClient.SqlParameterCollection
RDO.rdoPreparedStatement System.Data.SqlClient.SqlCommand
RDO.rdoQuery System.Data.SqlClient.SqlCommand

The RDO to ADO.NET upgrade also covers the possibility to use the MSRDC control for this particular technology. The mappings are described below:

Class Maps to
MSRDC.MSRDC Artinsoft.VB6.Gui.DataHelper

In addition, conversion rules apply changes over specific pattern in the source code related to RDO code:

Visual Basic 6 pattern Maps to
RDO Resultset loops
  • Conversion to foreach iterations
  • Conversion to Datareader (applied if the recordset is used to read information only).

A brief source sample of this feature:

Original VB6 Code:

Public recRecordset As RDO.rdoResultset
Public RDOConnection As New RDO.RDOConnection

Private Sub Form_Load()
    
    Set RDOConnection = New RDO.RDOConnection
    RDOConnection.CursorDriver = rdUseClientBatch
    RDOConnection.Connect = "uid=ftt_uwee;pwd=fttuwee;driver={SQL SERVER}; server=AISCRIT11\FTT;database=Northwind;"

    RDOConnection.EstablishConnection rdDriverNoPrompt, False

    Set recRecordset = RDOConnection.OpenResultset("select * from Customers", rdOpenKeyset, _
                  rdConcurBatch)
    
    recRecordset.MoveFirst
End Sub

Resulting VB.NET Code:

Public recRecordset As DataSet
Private _RDOConnection As SqlConnection = Nothing

Private Sub Form1_Load(ByVal eventSender As Object, ByVal eventArgs As EventArgs) Handles MyBase.Load
        
    RDOConnection = New SqlConnection()
    RDOConnection.CursorDriver = RDO.CursorDriverConstants.rdUseClientBatch
    RDOConnection.Connect = "uid=ftt_uwee;pwd=fttuwee;driver={SQL SERVER}; server=AISCRIT11\FTT;database=Northwind;"
        RDOConnection.EstablishConnection(RDO.PromptConstants.rdDriverNoPrompt, False)
        
    Dim tempAdapter As SqlDataAdapter = New SqlDataAdapter("select * from Customers", RDOConnection)
    recRecordset = New DataSet
    tempAdapter.Fill(recRecordset)
        
'UPGRADE_ISSUE: (1040) MoveFirst function is not supported. More Information: http://www.vbtonet.com/ewis/ewi1040.aspx
    UpgradeStubs.RDO_rdoResultset.MoveFirst(recRecordset)
End Sub

Resulting C#.NET Code:

public DataSet recRecordset = null;
private SqlConnection _RDOConnection = null;

private void  Form1_Load( Object eventSender,  EventArgs eventArgs)
{
                    
    RDOConnection = new SqlConnection();
    RDOConnection.CursorDriver = RDO.CursorDriverConstants.rdUseClientBatch;
    RDOConnection.Connect = "uid=ftt_uwee;pwd=fttuwee;driver={SQL SERVER}; server=AISCRIT11\\FTT;database=Northwind;";
                RDOConnection.EstablishConnection(RDO.PromptConstants.rdDriverNoPrompt, false, null);
                    
    SqlDataAdapter tempAdapter = new SqlDataAdapter("select * from Customers", RDOConnection);
    recRecordset = new DataSet();
    tempAdapter.Fill(recRecordset);
                    
//UPGRADE_ISSUE: (1040) MoveFirst function is not supported. More Information: http://www.vbtonet.com/ewis/ewi1040.aspx
                    UpgradeStubs.RDO_rdoResultset.MoveFirst(recRecordset);
}

In comparison, this data access migration technique offers a limited conversion ratio and requires considerably more human efforts to achieve functional equivalence than the System.Data.Common approach. The main reason behind this situation is the lack of helper classes.

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