Querying with the DataReader
The CData ADO.NET Provider for SAS Xpt implements two ADO.NET interfaces you can use to retrieve data from SAS Xpt: SASXptDataAdapter and SASXptDataReader objects. Whereas SASXptDataAdapter objects retrieve a single result set of all the data that matches a query, SASXptDataReader objects fetch data in subset increments as needed.
Using the SASXptDataReader
The SASXptDataReader retrieves data faster than the SASXptDataAdapter because it can retrieve data in pages. As you read data from the SASXptDataReader, 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 SampleTable_1 table:
C#
string connectionString = "URI=C:\folder;"; using (SASXptConnection connection = new SASXptConnection(connectionString)) { SASXptCommand cmd = new SASXptCommand("SELECT * FROM SampleTable_1", connection); SASXptDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Console.WriteLine(String.Format("\t{0} --> \t\t{1}", rdr["Id"], rdr["Column1"])); } }
VB.NET
Dim connectionString As String = "URI=C:\folder;" Using connection As New SASXptConnection(connectionString) Dim cmd As New SASXptCommand("SELECT * FROM SampleTable_1", connection) Dim rdr As SASXptDataReader = cmd.ExecuteReader() While rdr.Read() Console.WriteLine([String].Format(vbTab & "{0} --> " & vbTab & vbTab & "{1}", rdr("Id"), rdr("Column1"))) End While End Using