The CData ADO.NET Provider for ServiceNow implements two ADO.NET interfaces you can use to retrieve data from ServiceNow: ServiceNowDataAdapter and ServiceNowDataReader objects. Whereas ServiceNowDataAdapter objects retrieve a single result set of all the data that matches a query, ServiceNowDataReader objects fetch data in subset increments as needed.

Using the ServiceNowDataReader

The ServiceNowDataReader retrieves data faster than the ServiceNowDataAdapter because it can retrieve data in pages. As you read data from the ServiceNowDataReader, it periodically requests the next page of results from the data source, if required. This causes results to be returned at a faster rate. The following example selects all the columns from the incident table:

C#

string connectionString = "InitiateOAuth=GETANDREFRESH;OAuthClientId=MyClientId;OAuthClientSecret=MyClientSecret;User=MyUser;Password=MyPassword;Url=https://MyInstance12345.service-now.com/;";

using (ServiceNowConnection connection = new ServiceNowConnection(connectionString)) {
  ServiceNowCommand cmd = new ServiceNowCommand("SELECT * FROM incident", connection);
  
  ServiceNowDataReader rdr = cmd.ExecuteReader();

  while (rdr.Read()) {
    Console.WriteLine(String.Format("\t{0} --> \t\t{1}", rdr["sys_id"], rdr["priority"]));
  }
}

VB.NET

Dim connectionString As String = "InitiateOAuth=GETANDREFRESH;OAuthClientId=MyClientId;OAuthClientSecret=MyClientSecret;User=MyUser;Password=MyPassword;Url=https://MyInstance12345.service-now.com/;"

Using connection As New ServiceNowConnection(connectionString)
  Dim cmd As New ServiceNowCommand("SELECT * FROM incident", connection)

  Dim rdr As ServiceNowDataReader = cmd.ExecuteReader()

  While rdr.Read()
    Console.WriteLine([String].Format(vbTab & "{0} --> " & vbTab & vbTab & "{1}", rdr("sys_id"), rdr("priority")))
  End While
End Using