Datenbankzugriff über ADO.net

static void ADOnetWithOutNULL(Args _args)
{
    str 100 serverName = @"AX2012R2A";
    str 100 dataBaseName = "ImportDatabase";
    System.Data.SqlClient.SqlConnectionStringBuilder connectionStringBuilder;
    System.Data.SqlClient.SqlConnection connection;
    System.Data.SqlClient.SqlCommand command;
    System.Data.SqlClient.SqlDataReader dataReader;
    str sqlQuery;
    System.Exception InteropException;
    Counter c;
    real realValue;
    str 100 strValue;
    int intValue;
    utcDateTime dateTimeValue;
    date dateValue;
   

    void cleanUp()
    {
        if(dataReader) dataReader.Dispose();
        if(connection) connection.Dispose();
        if(command)    command.Dispose();       
       
        CodeAccessPermission::revertAssert();       
       
        interopException = CLRInterop::getLastException();
        if(interopException)
        {
            while(!CLRInterop::isNull(interopException.get_InnerException()))
            {
                error(CLRInterop::getAnyTypeForObject(interopException.get_Message()));
            }
        }
    }
   
    new InteropPermission( InteropKind::ClrInterop ).assert();

    connectionStringBuilder = new System.Data.SqlClient.SqlConnectionStringBuilder();
    connectionStringBuilder.set_DataSource(serverName);
    connectionStringBuilder.set_InitialCatalog(databaseName);
    connectionStringBuilder.set_IntegratedSecurity(true);

    // Because NULL-Values may cause errors, IsNull-Statement is used
    sqlQuery = @" SELECT
                   isNull([CustomerID], 0) AS CustomerID
                  ,isNull([CustomerName], '') AS CustomerName
                  ,isNull([LastInvoiceDateTime], '9999-01-01 01:01:01.001') AS LastInvoiceDateTime
                  ,isNull([LastCollectionLetterDate], '9999-01-01 01:01:01.001') AS LastCollectionLetterDate
                  ,isNull([CreditLimit], 0) AS CreditLimit
                  FROM [Customers]";


    try
    {
        // Connection
        connection = new System.Data.SqlClient.SqlConnection(connectionStringBuilder.ToString());
        connection.Open();

        try
        {
            // Create statement
            command = connection.CreateCommand();
            command.set_CommandText(sqlQuery);

            // Create reader
            dataReader = command.ExecuteReader();
           
            try
            {
                while (dataReader.Read())
                {
                    c++;

                    // Read records
                    strValue = CLRInterop::getAnyTypeForObject( dataReader.get_Item("CustomerName"));
                    intValue = CLRInterop::getAnyTypeForObject( dataReader.get_Item("CustomerID"));
                    realValue = CLRInterop::getAnyTypeForObject( dataReader.get_Item("CreditLimit"));
                    dateValue = CLRInterop::getAnyTypeForObject( dataReader.get_Item("LastCollectionletterDate"));
                    dateTimeValue = CLRInterop::getAnyTypeForObject( dataReader.get_Item("LastInvoiceDateTime"));
                   
                    // Truncate string values
                    strValue = strRTrim(strValue);

                    // Output
                    info(strFmt("Integer: %1 String: %2 Real: %3 DateTime: %4 Date: %5", intValue,
                                                                                         strValue,
                                                                                         realValue,
                                                                                         dateTimeValue,
                                                                                         dateValue));
                }
            }
            catch (Exception::CLRError)
            {
                cleanUp();
                throw error("Wrong fields");
            }               
        }
        catch (Exception::CLRError)
        {
            cleanUp();
            throw error(strFmt("The SQL-Statement seems to be wrong: %1", sqlQuery));
        }
    }
    catch(Exception::CLRError)
    {
        cleanUp();
        throw error(strFmt('Connection to database "%1/%2" failed', serverName, databaseName));
    }

    cleanUp();

    info(strFmt("Records read: %1", c));

}