SQL事务机制

                DateTime indate = CheckedDateFunction();
                string connstr = Connectionstr.ConnectionString;
                OleDbConnection oleconn = new OleDbConnection(connstr);

                oleconn.Open();
                OleDbCommand myCommand = oleconn.CreateCommand();
                OleDbTransaction myTrans;
                myTrans = oleconn.BeginTransaction();
                myCommand.Connection = oleconn;
                myCommand.Transaction = myTrans;


                try
                ...{
                    myCommand.CommandText = "Insert Into ClientRecord(ClientID,ClientName,RoomID,[ClientMemo],InDate,CheckDate,Settle) values( '" + txtClientID.Text + "'" +
                                                                                                                              ",'" + txtClientName.Text + "'" +
                                                                                                                              ",'" + txtNum.Text + "'" +
                                                                                                                              ",'" + txtMemo.Text + "'" +
                                                                                                                              ",'" + indate.ToString() + "'" +
                                                                                                                              ",Now(),0 ) ";//[Memo]不能少了中括号
                    string inserttemp = myCommand.ExecuteNonQuery().ToString();



                    if (int.Parse(inserttemp) == 1)
                    ...{
                        myCommand.CommandText = "Insert Into Client(ClientID,ClientName,ClientSex,ClientAddress) values('" + txtClientID.Text + "'" +
                                                                                                                       ",'" + txtClientName.Text + "'" +
                                                                                                                       ",'" + cboSex.Text + "'" +
                                                                                                                       ",'" + cboClientAddress.Text + "')";
                        string insertclientinfo = myCommand.ExecuteNonQuery().ToString();

                        if (int.Parse(insertclientinfo) == 1)
                        ...{
                            myCommand.CommandText = "Update Room Set ActuallyCount = [ActuallyCount] +" + Convert.ToInt16(cboPutupPeople.Text) + ",RoomState = 1 where  RoomNumber = '" + txtNum.Text.ToString() + "'";
                            myCommand.ExecuteNonQuery();
                            myTrans.Commit();
                            MessageBox.Show("操作成功!欢迎光临!", "成功提示");
                            this.Close();
                        }
                        else
                        ...{
                            myTrans.Rollback();
                            return;
                        }
                    }
                    else
                    ...{
                        myTrans.Rollback();
                        return;
                    }

                }
                catch (Exception ex)
                ...{
                    myTrans.Rollback();
                    MessageBox.Show("Error:" + ex.ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
                finally
                ...{
                    oleconn.Close();
                }