Querying with the DataReader
The CData ADO.NET Provider for SAS Data Sets implements two ADO.NET interfaces you can use to retrieve data from SAS Data Sets: SASDataSetsDataAdapter and SASDataSetsDataReader objects. Whereas SASDataSetsDataAdapter objects retrieve a single result set of all the data that matches a query, SASDataSetsDataReader objects fetch data in subset increments as needed.
Using the SASDataSetsDataReader
The SASDataSetsDataReader retrieves data faster than the SASDataSetsDataAdapter because it can retrieve data in pages. As you read data from the SASDataSetsDataReader, 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 = "URI=C:\myfolder;"; using (SASDataSetsConnection connection = new SASDataSetsConnection(connectionString)) { SASDataSetsCommand cmd = new SASDataSetsCommand("SELECT * FROM Account", connection); SASDataSetsDataReader 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 = "URI=C:\myfolder;" Using connection As New SASDataSetsConnection(connectionString) Dim cmd As New SASDataSetsCommand("SELECT * FROM Account", connection) Dim rdr As SASDataSetsDataReader = cmd.ExecuteReader() While rdr.Read() Console.WriteLine([String].Format(vbTab & "{0} --> " & vbTab & vbTab & "{1}", rdr("Id"), rdr("Name"))) End While End Using