Querying with the DataReader
The CData ADO.NET Provider for Informix implements two ADO.NET interfaces you can use to retrieve data from Informix: InformixDataAdapter and InformixDataReader objects. Whereas InformixDataAdapter objects retrieve a single result set of all the data that matches a query, InformixDataReader objects fetch data in subset increments as needed.
Using the InformixDataReader
The InformixDataReader retrieves data faster than the InformixDataAdapter because it can retrieve data in pages. As you read data from the InformixDataReader, 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 [informix].Books table:
C#
string connectionString = "Server=10.0.1.2;Port=50000;User=admin;Password=admin;Database=test"; using (InformixConnection connection = new InformixConnection(connectionString)) { InformixCommand cmd = new InformixCommand("SELECT * FROM [informix].Books", connection); InformixDataReader rdr = cmd.ExecuteReader(); while (rdr.Read()) { Console.WriteLine(String.Format("\t{0} --> \t\t{1}", rdr["Id"], rdr["Author"])); } }
VB.NET
Dim connectionString As String = "Server=10.0.1.2;Port=50000;User=admin;Password=admin;Database=test" Using connection As New InformixConnection(connectionString) Dim cmd As New InformixCommand("SELECT * FROM [informix].Books", connection) Dim rdr As InformixDataReader = cmd.ExecuteReader() While rdr.Read() Console.WriteLine([String].Format(vbTab & "{0} --> " & vbTab & vbTab & "{1}", rdr("Id"), rdr("Author"))) End While End Using