public override bool ChangePassword(string username, string oldPwd, string newPwd)
        {
            if (!ValidateUser(username, oldPwd))
                return false;

            ValidatePasswordEventArgs args =
                new ValidatePasswordEventArgs(username, newPwd, true);

            OnValidatingPassword(args);
            if (args.Cancel)
            {
                if (args.FailureInformation != null)
                    throw args.FailureInformation;

                throw new MembershipPasswordException("Change password canceled due to new password validation failure.");
            }

            int rowsAffected = 0;
            using (Database db = new MySqlDatabase())
            {
                rowsAffected = db.ChangePassword(username, _applicationName, newPwd);
            }
            if (rowsAffected > 0)
                return true;

            return false;	// update failed
        }