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

Using the GraphQLDataAdapter

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

The following example selects the Name and Email columns of the Users table:

C#

string connectionString = "AuthScheme=OAuth;OAuthVersion=2.0;CallbackURL=http://localhost:33333;OauthClientId=MyOAuthClientId;OAuthClientSecret=MyOAuthClientSecret;OAuthAccessTokenURL=https://mysite.com/login/oauth/access_token;";

using (GraphQLConnection connection = new GraphQLConnection(connectionString)) {
  GraphQLDataAdapter dataAdapter = new GraphQLDataAdapter(
  "SELECT Name, Email FROM Users", connection);

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

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

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

VB.NET

Dim connectionString As String = "AuthScheme=OAuth;OAuthVersion=2.0;CallbackURL=http://localhost:33333;OauthClientId=MyOAuthClientId;OAuthClientSecret=MyOAuthClientSecret;OAuthAccessTokenURL=https://mysite.com/login/oauth/access_token;"

Using connection As New GraphQLConnection(connectionString)
  Dim dataAdapter As New GraphQLDataAdapter("SELECT Name, Email FROM Users", connection)

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

  Console.WriteLine("Contents of Users.")

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