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

Using the DatabricksDataReader

The DatabricksDataReader retrieves data faster than the DatabricksDataAdapter because it can retrieve data in pages. As you read data from the DatabricksDataReader, 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 [CData].[Sample].Customers table:

C#

string connectionString = "Server=127.0.0.1;HTTPPath=MyHTTPPath;User=MyUser;Token=MyToken;";

using (DatabricksConnection connection = new DatabricksConnection(connectionString)) {
  DatabricksCommand cmd = new DatabricksCommand("SELECT * FROM [CData].[Sample].Customers", connection);
  
  DatabricksDataReader rdr = cmd.ExecuteReader();

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

VB.NET

Dim connectionString As String = "Server=127.0.0.1;HTTPPath=MyHTTPPath;User=MyUser;Token=MyToken;"

Using connection As New DatabricksConnection(connectionString)
  Dim cmd As New DatabricksCommand("SELECT * FROM [CData].[Sample].Customers", connection)

  Dim rdr As DatabricksDataReader = cmd.ExecuteReader()

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