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

Using the PostgreSQLDataAdapter

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 PostgreSQLDataAdapter is slower than the PostgreSQLDataReader 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=postgres;Password=admin;Database=postgres;Server=127.0.0.1;Port=5432";

using (PostgreSQLConnection connection = new PostgreSQLConnection(connectionString)) {
  PostgreSQLDataAdapter dataAdapter = new PostgreSQLDataAdapter(
  "SELECT ShipName, ShipCity FROM \"postgres\".\"schema01\".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=postgres;Password=admin;Database=postgres;Server=127.0.0.1;Port=5432"

Using connection As New PostgreSQLConnection(connectionString)
  Dim dataAdapter As New PostgreSQLDataAdapter("SELECT ShipName, ShipCity FROM \"postgres\".\"schema01\".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