ADO.NET Provider for Greenplum

Build 21.0.7930

Querying with the DataAdapter

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

Using the GreenplumDataAdapter

Use the adapter's Fill method to retrieve data from the data source. An empty DataTable instance is passed as an argument to the Fill method. When the method returns, the DataTable instance is populated with the queried data. Note that the GreenplumDataAdapter is slower than the GreenplumDataReader because the Fill method needs to retrieve all data from the data source before returning.

The following example selects the ShipName and ShipCity columns of the Orders table:

C#

string connectionString = "User=user;Password=admin;Database=dbname;Server=127.0.0.1;Port=5432";

using (GreenplumConnection connection = new GreenplumConnection(connectionString)) {
  GreenplumDataAdapter dataAdapter = new GreenplumDataAdapter(
  "SELECT ShipName, ShipCity FROM \"template1\".\"public\".Orders", connection);

  DataTable table = new DataTable();
  dataAdapter.Fill(table);

  Console.WriteLine("Contents of Orders.");

  foreach (DataRow row in table.Rows) {
    Console.WriteLine("{0}: {1}", row["ShipName"], row["ShipCity"]);
  }
}

VB.NET

Dim connectionString As String = "User=user;Password=admin;Database=dbname;Server=127.0.0.1;Port=5432"

Using connection As New GreenplumConnection(connectionString)
  Dim dataAdapter As New GreenplumDataAdapter("SELECT ShipName, ShipCity FROM \"template1\".\"public\".Orders", connection)

  Dim table As New DataTable()
  dataAdapter.Fill(table)

  Console.WriteLine("Contents of Orders.")

  For Each row As DataRow In table.Rows
    Console.WriteLine("{0}: {1}", row("ShipName"), row("ShipCity"))
  Next
End Using

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Build 21.0.7930