Querying with the DataReader
The ADO.NET Provider for TIBCO(R) Data Virtualization implements two ADO.NET interfaces you can use to retrieve data from TDV: CompositeDataAdapter and CompositeDataReader objects. Whereas CompositeDataAdapter objects retrieve a single result set of all the data that matches a query, CompositeDataReader objects fetch data in subset increments as needed.
Using the CompositeDataReader
The CompositeDataReader retrieves data faster than the CompositeDataAdapter because it can retrieve data in pages. As you read data from the CompositeDataReader, 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 Products table:
C#
string connectionString = "Host=myHost;Domain=myDomain;DataSource=myDataSource;User=myUser;Password=myPassword";
using (CompositeConnection connection = new CompositeConnection(connectionString)) {
CompositeCommand cmd = new CompositeCommand("SELECT * FROM Products", connection);
CompositeDataReader rdr = cmd.ExecuteReader();
while (rdr.Read()) {
Console.WriteLine(String.Format("\t{0} --> \t\t{1}", rdr["Id"], rdr["ProductName"]));
}
}
VB.NET
Dim connectionString As String = "Host=myHost;Domain=myDomain;DataSource=myDataSource;User=myUser;Password=myPassword"
Using connection As New CompositeConnection(connectionString)
Dim cmd As New CompositeCommand("SELECT * FROM Products", connection)
Dim rdr As CompositeDataReader = cmd.ExecuteReader()
While rdr.Read()
Console.WriteLine([String].Format(vbTab & "{0} --> " & vbTab & vbTab & "{1}", rdr("Id"), rdr("ProductName")))
End While
End Using