ADO.NET Provider for Apache HBase

Build 21.0.7930

Querying with the DataReader

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

Using the ApacheHBaseDataReader

The ApacheHBaseDataReader retrieves data faster than the ApacheHBaseDataAdapter because it can retrieve data in pages. As you read data from the ApacheHBaseDataReader, 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 Account table:

C#

string connectionString = "Server=127.0.0.1;Port=8080;";

using (ApacheHBaseConnection connection = new ApacheHBaseConnection(connectionString)) {
  ApacheHBaseCommand cmd = new ApacheHBaseCommand("SELECT * FROM Account", connection);
  
  ApacheHBaseDataReader rdr = cmd.ExecuteReader();

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

VB.NET

Dim connectionString As String = "Server=127.0.0.1;Port=8080;"

Using connection As New ApacheHBaseConnection(connectionString)
  Dim cmd As New ApacheHBaseCommand("SELECT * FROM Account", connection)

  Dim rdr As ApacheHBaseDataReader = cmd.ExecuteReader()

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

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Build 21.0.7930