ADO.NET Provider for AlloyDB

Build 23.0.8770

Querying with the DataReader

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

Using the AlloyDBDataReader

The AlloyDBDataReader retrieves data faster than the AlloyDBDataAdapter because it can retrieve data in pages. As you read data from the AlloyDBDataReader, 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 "alloydb"."schema01".Orders table:

C#

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

using (AlloyDBConnection connection = new AlloyDBConnection(connectionString)) {
  AlloyDBCommand cmd = new AlloyDBCommand("SELECT * FROM \"alloydb\".\"schema01\".Orders", connection);
  
  AlloyDBDataReader rdr = cmd.ExecuteReader();

  while (rdr.Read()) {
    Console.WriteLine(String.Format("\t{0} --> \t\t{1}", rdr["ShipName"], rdr["ShipCity"]));
  }
}

VB.NET

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

Using connection As New AlloyDBConnection(connectionString)
  Dim cmd As New AlloyDBCommand("SELECT * FROM \"alloydb\".\"schema01\".Orders", connection)

  Dim rdr As AlloyDBDataReader = cmd.ExecuteReader()

  While rdr.Read()
    Console.WriteLine([String].Format(vbTab & "{0} --> " & vbTab & vbTab & "{1}", rdr("ShipName"), rdr("ShipCity")))
  End While
End Using

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Build 23.0.8770