If you don't specify a ConnectionType AdoNetAppender defaults to using OleDbConnection which has a different connection string format than the more common SqlConnection. Are you sure you want to use OleDbConnection?
Why not write a simple ConsoleApplication to test your code and look at the configuration output log4net writes to Console.Out? class Program { private static AdoNetAppender _sqlDatabaseAppender = new AdoNetAppender(); static void Main(string[] args) { LogLog.InternalDebugging = true; LogLog.EmitInternalMessages = true; ConfigureDatabaseAppender("..."); ILog log = LogManager.GetLogger(typeof(Program)); log.Debug("Hello World"); Console.ReadLine(); } public static void ConfigureDatabaseAppender(string connString) { // snip ________________________________ From: James Green <james.gr...@occam-dm.com> To: Log4NET User <log4net-user@logging.apache.org> Sent: Monday, June 15, 2009 12:04:16 PM Subject: RE: Using AdoNetAppender I think I'm going to have to try the config file method first. I'm wrapping log4net and I don't want to cause every consuming component to require loads of config information in it just for logging purposes. Everything else is a sinch to configure in code, save for this appender ... *sigh* ... Cheers, James.