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

Using the GoogleBigQueryDataReader

The GoogleBigQueryDataReader retrieves data faster than the GoogleBigQueryDataAdapter because it can retrieve data in pages. As you read data from the GoogleBigQueryDataReader, 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 [publicdata].[samples].github_nested table:

C#

string connectionString = "InitiateOAuth=GETANDREFRESH;ProjectId=NameOfProject;DatasetId=NameOfDataset;";

using (GoogleBigQueryConnection connection = new GoogleBigQueryConnection(connectionString)) {
  GoogleBigQueryCommand cmd = new GoogleBigQueryCommand("SELECT * FROM [publicdata].[samples].github_nested", connection);
  
  GoogleBigQueryDataReader rdr = cmd.ExecuteReader();

  while (rdr.Read()) {
    Console.WriteLine(String.Format("\t{0} --> \t\t{1}", rdr["actor.attributes.email"], rdr["repository.name"]));
  }
}

VB.NET

Dim connectionString As String = "InitiateOAuth=GETANDREFRESH;ProjectId=NameOfProject;DatasetId=NameOfDataset;"

Using connection As New GoogleBigQueryConnection(connectionString)
  Dim cmd As New GoogleBigQueryCommand("SELECT * FROM [publicdata].[samples].github_nested", connection)

  Dim rdr As GoogleBigQueryDataReader = cmd.ExecuteReader()

  While rdr.Read()
    Console.WriteLine([String].Format(vbTab & "{0} --> " & vbTab & vbTab & "{1}", rdr("actor.attributes.email"), rdr("repository.name")))
  End While
End Using