SqlConnection myCon2 = new SqlConnection();
                    myCon2.ConnectionString = "Persist Security Info=False;User id=sa;pwd=111111;database=message;server=(local)";
                    myCon2.Open();

                    Console.WriteLine("请输入员工编号：");
                    string user_id = Console.ReadLine();

                    SqlDataAdapter adp = new SqlDataAdapter();
                    DataTable dt = myCon2.GetSchema();

                    try
                    {
                        SqlCommand cmd = new SqlCommand("select * from user_id" , myCon2);
                        cmd.ExecuteNonQuery();
                    }
                    catch (SqlException ex) {
                        switch (ex.Number) { 
                            case 1146:
                                Console.WriteLine("无此表，创建表");
                                string mySelectQuery="CREATE TABLE user_id(usermessage VARCHAR(MAX))";
                                SqlCommand cmd = new SqlCommand(mySelectQuery, myCon2);
                                cmd.ExecuteNonQuery();
                                Console.Read();
                                break;
                            default:
                                break;
                        }
                    }