UPDATE SIMPLE_LONG SET VALUE_I = 111, VALUE_D = 111, VALUE_S = '111'

        public static void UpdateSimpleLong(int aValue)
        {
            var qUpdateSingle = "UPDATE SIMPLE_LONG SET " +
                                "VALUE_I = @P_VALUE_I, VALUE_D = @P_VALUE_D, VALUE_S = @P_VALUE_S";
            var parameters = new[]
                {
                    new FbParameter("@P_VALUE_I", aValue),
                    new FbParameter("@P_VALUE_D", (double) aValue),
                    new FbParameter("@P_VALUE_S", aValue.ToString())
                };

            var timerUpdate = new Stopwatch();
            timerUpdate.Start();
            var records = ExecuteNonQuery(qUpdateSingle, connectionString, parameters);
            timerUpdate.Stop();

            Console.WriteLine("Changed records: " + records + " = " + timerUpdate.ElapsedMilliseconds/1000 + " sec");            
        }

        private static int ExecuteNonQuery(string aSQL, string aConnectionString, FbParameter[] aParameters)
        {
            using (var connection_ = new FbConnection(aConnectionString))
            {                
                var cmd = new FbCommand(aSQL, connection_);
                cmd.Parameters.AddRange(aParameters);
                connection_.Open();
                return cmd.ExecuteNonQuery();
            }
        }

return cmd.ExecuteNonQuery();

initial catalog=D:\TEST.FDB;user id=SYSDBA;password=masterkey;port number=3050;server type=Default;dialect=3;pooling=True