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

Using the GoogleSpannerDataAdapter

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 GoogleSpannerDataAdapter is slower than the GoogleSpannerDataReader because the Fill method needs to retrieve all data from the data source before returning.

The following example selects the Name and TotalDue columns of the Customer table:

C#

string connectionString = "ProjectId='project1';InstanceId='instance1';Database='db1';OAuthClientId='757060765381';OauthClientSecret='abc';";

using (GoogleSpannerConnection connection = new GoogleSpannerConnection(connectionString)) {
  GoogleSpannerDataAdapter dataAdapter = new GoogleSpannerDataAdapter(
  "SELECT Name, TotalDue FROM [CData].[GoogleSpanner].Customer", connection);

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

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

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

VB.NET

Dim connectionString As String = "ProjectId='project1';InstanceId='instance1';Database='db1';OAuthClientId='757060765381';OauthClientSecret='abc';"

Using connection As New GoogleSpannerConnection(connectionString)
  Dim dataAdapter As New GoogleSpannerDataAdapter("SELECT Name, TotalDue FROM [CData].[GoogleSpanner].Customer", connection)

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

  Console.WriteLine("Contents of Customer.")

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