如何追踪每一笔记录的来龙去脉：一个完整的Audit Logging解决方案[下篇]

通过第一部分的介绍，我们对这个Audit Logging解决方案的原理有了较为全面的了解，接下来我们将通过一个简单的Sample来进一步介绍如何在一个具体的应用中如何实现这样一个Audit Logging。

我们沿用在Part I提出的Order management 场景，为了简单起见，我们通过一个Console application来模拟。在这个Application中，你将会看到如何以一种离线的模式操作数据库，如何Log这些操作。

我们首先来介绍Sample程序的结构（如下图）。整个Solution 一共包括两个Project，一个Console application，另一个是用以管理和定义Stored Procedure和Trigger的Database project。我们现在就来一步步实现这样一个Order management的简单的应用。Source Code从Artech.WCFService.zip下载。

一．定义一个轻型的Data access 的Helper class。

在Part I中我提到过这样一个Helper class，虽然这不是本篇所要介绍的重点，但是为了让读者能够较为全面地了解整个处理流程，在这里我对她作一个简单的介绍。

我在前一阵子，写过一篇叫做[原创]我的ORM: 开发自己的Data Access Application Block 的文章，在这片文章中我开发了一个自定义的DAB。我这个Data access helper便是采用里面提出的思想，实现了其中一小部分功能：Data retrieval， Update Dataset和Transaction。力求简洁，我剔出掉其中可配置的data mapping部分采用hard coding的方式实现Dataset和Stored procedure的Mapping。

通过这个Helper class，你可以调用UpdateData方法把对一个Table作的修改向数据库提交。这个方法的思路是这样的：我们对该Table的增加、修改和删除均定义了一个Stored procedure，我们假设Table name和Stored procedure name之间，Stored procedure的每个Parameter 的名称和Table中的Field name和DataRowVersion存在一个Mapping。比如T_ORDER对应的增加、修改和删除stored procedure分别为sp_order_i，sp_order_u和sp_order_d；stored procedure的参数@p_order_id对应的Source column为ORDER_ID, SourceVersion为DataRowVersion.Current，而参数@o_order_id对应的SourceVersion为DataRowVersion.Original。有了这样一个Mapping为前提，相信大家对Helper class的实现原理应该想象得到。当然要使我们的Stored procedure满足这样一个Mapping，靠我们手工的方式来定义每个stored procedure在一个真正的application是不现实的，一般地这些都是通过我们根据具体的Mapping关系开发的生成器生成的。像本Sample的所有stored procedure和trigger也都是通过Generator生成的。

下面是整个Helper class的实现，不算太复杂，有兴趣的话可以看看。否则敬请略过。

using System;
using System.Collections.Generic;
using System.Text;
using System.Configuration;
using System.Data;
using System.Data.Common;
using System.Data.SqlClient;

namespace Artech.AuditLogging.ConsoleApp
{
    public class DataAccessHelper:IDisposable
    {
        Private Fields#region Private Fields
        private bool _isDisposed;
        private string _connectionString;
        private DbConnection _connection;
        private DbTransaction _transaction;
        private DbProviderFactory _dbProviderFactory;
        private DbDataAdapter _dbDataAdapter;
        #endregion

        Public Properties#region Public Properties

        public DbDataAdapter DbDataAdapter
        {
            get
            {
                if (this._dbDataAdapter == null)
                {
                    this._dbDataAdapter = this.DbProviderFactory.CreateDataAdapter();
                }

                return this._dbDataAdapter;
            }
        }

        public DataAccessHelper()
        {
            this._dbProviderFactory = DbProviderFactories.GetFactory(ConfigurationManager.ConnectionStrings[0].ProviderName);
            this._connectionString = ConfigurationManager.ConnectionStrings[0].ConnectionString;
        }

        //Data Access Provider Factory which is responsible for creating provider based ADO.NET conponent.
        public DbProviderFactory DbProviderFactory
        {
            get
            {
                return this._dbProviderFactory;
            }  
        }

        public DbConnection Connection
        {
            get
            {
                if (this._connection == null)
                {
                    this._connection = this.DbProviderFactory.CreateConnection();
                    this._connection.ConnectionString = this._connectionString;
                }

                if (this._connection.State != ConnectionState.Open)
                {
                    this._connection.Open();
                }

                return this._connection;
            }
        }
        #endregion

        Transaction Operations#region Transaction Operations

        public void BeginTransaction()
        {
            this._transaction = this.Connection.BeginTransaction();
        }

        public void Rollback()
        {
            if (this._transaction != null)
            {
                this._transaction.Rollback();
            }
        }

        public void Commit()
        {
            if (this._transaction != null)
            { 
                this._transaction.Commit();
            }
        }
        #endregion

        Data Mapping#region Data Mapping

        private string GetSourceCoulmnName(string patameterName)
        {
            //@p_abc_def|o_abc_def=>ABC_DEF
            return patameterName.Substring(3, patameterName.Length - 3).ToUpper();
        }

        public  DataRowVersion GetSourceVersion(string parameterName)
        {
            //p_abc_def=>DataRowVersion.Current
            //o_abc_default=>DataRowVersion.Original
            if (parameterName.StartsWith("@o"))
            {
                return DataRowVersion.Original;
            }
            return DataRowVersion.Current;
        }

        private string GetSelectStoredProcedureName(string tableName)
        {
            //T_ABC_DEF=>sp_abc_def_s
            return string.Format("sp_{0}_s", tableName.Substring(2, tableName.Length - 2).ToLower());
        }

        private string GetInsertStoredProcedureName(string tableName)
        {
            //T_ABC_DEF=>sp_abc_def_i
            return string.Format("sp_{0}_i", tableName.Substring(2, tableName.Length - 2).ToLower());
        }

        private string GetModifyStoredProcedureName(string tableName)
        {
            //T_ABC_DEF=>sp_abc_def_u
            return string.Format("sp_{0}_u", tableName.Substring(2, tableName.Length - 2).ToLower());
        }

        private string GetDeleteStoredProcedureName(string tableName)
        {
            //T_ABC_DEF=>sp_abc_def_d
            return string.Format("sp_{0}_d", tableName.Substring(2, tableName.Length - 2).ToLower());
        }
        #endregion

        Discovery Parameter#region Discovery Parameter

        private void DiscoverParameters(DbCommand command)
        {
            if (command.Connection.State != ConnectionState.Open)
            {
                command.Connection.Open();
            }
            SqlCommandBuilder.DeriveParameters(command as SqlCommand);
        }

        #endregion

        Public Methods#region Public Methods

        public void UpdateData(DataTable table)
        {
            
            //Create the three commands of the database data adapter.
            DbCommand insertCommand = this.Connection.CreateCommand();
            DbCommand updateCommand = this.Connection.CreateCommand();
            DbCommand deleteCommand = this.Connection.CreateCommand();

            //Specify the command type.
            insertCommand.CommandType = CommandType.StoredProcedure;
            updateCommand.CommandType = CommandType.StoredProcedure;
            deleteCommand.CommandType = CommandType.StoredProcedure;

            insertCommand.UpdatedRowSource = UpdateRowSource.OutputParameters;

            //Specify the command text.
            insertCommand.CommandText = this.GetInsertStoredProcedureName(table.TableName);
            updateCommand.CommandText = this.GetModifyStoredProcedureName(table.TableName);
            deleteCommand.CommandText = this.GetDeleteStoredProcedureName(table.TableName);
           
            //Set the parameters of the insert command.
            if (table.GetChanges(DataRowState.Added) != null)
            {
                if (this._transaction != null)
                {
                    insertCommand.Transaction = this._transaction;
                }
              this.DiscoverParameters(insertCommand);
              //Specify the Source column and source version for insert command based paramemters.
              foreach (DbParameter parameter in insertCommand.Parameters)
              {
                  if (parameter.Direction == ParameterDirection.ReturnValue)
                  {
                      continue;
                  }
                  parameter.SourceColumn = this.GetSourceCoulmnName(parameter.ParameterName);
                  parameter.SourceVersion = this.GetSourceVersion(parameter.ParameterName);
              }
            }

            //Set the parameters of the update command.
            if (table.GetChanges(DataRowState.Modified) != null)
            {
                if (this._transaction != null)
                {
                    updateCommand.Transaction = this._transaction;
                }

                this.DiscoverParameters(updateCommand);
                //Specify the Source column and source version for update command based paramemters.
                foreach (DbParameter parameter in updateCommand.Parameters)
                {
                    if (parameter.Direction == ParameterDirection.ReturnValue)
                    {
                        continue;
                    }
                    parameter.SourceColumn = this.GetSourceCoulmnName(parameter.ParameterName);
                    parameter.SourceVersion = this.GetSourceVersion(parameter.ParameterName);
                }              
            }

            //Set the parameters of the delete command.
            if (table.GetChanges(DataRowState.Deleted) != null)
            {
                if (this._transaction != null)
                {
                    deleteCommand.Transaction = this._transaction;
                }
                this.DiscoverParameters(deleteCommand);
                //Specify the Source column and source version for delete command based paramemters.
                foreach (DbParameter parameter in deleteCommand.Parameters)
                {
                    if (parameter.Direction == ParameterDirection.ReturnValue)
                    {
                        continue;
                    }
                    parameter.SourceColumn = this.GetSourceCoulmnName(parameter.ParameterName);
                    parameter.SourceVersion = this.GetSourceVersion(parameter.ParameterName);
                }    

            }              

            //Evaluate the commands for the database adapter.
            this.DbDataAdapter.InsertCommand = insertCommand;
            this.DbDataAdapter.UpdateCommand = updateCommand;
            this.DbDataAdapter.DeleteCommand = deleteCommand;

            //Execute update.
            this.DbDataAdapter.Update(table);            
        }

        public void FillData(DataTable table, CommandType commandType, string commandText, IDictionary<string, object> parameters)
        {
            DbCommand command = this.Connection.CreateCommand();
            command.CommandType = commandType;
            command.CommandText = commandText;

            foreach (string parameterName in parameters.Keys)
            {
                DbParameter parameter = this.DbProviderFactory.CreateParameter();
                parameter.ParameterName = parameterName;
                parameter.Value = parameters[parameterName];
            }

            this.DbDataAdapter.SelectCommand = command;
            this.DbDataAdapter.Fill(table);
        }
        #endregion

        IDisposable Members#region IDisposable Members

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        private void Dispose(bool disposing)
        {
            if (!this._isDisposed)
            {
                if (disposing)
                {
                    if (this._connection != null)
                    {
                        if (this._connection.State == ConnectionState.Open)
                        {
                            this._connection.Close();
                        }
                    }

                    if (this._transaction != null)
                    {
                        this._transaction.Dispose();
                    }
                }
            }
            this._isDisposed = true;
        }

        #endregion
    }
}

二．定义Dataset

我们根据数据库中Table的结构定义一个具有相同结构的strongly typed dataset：OrderDataSet.

为了保证数据的完整性，我们必须为两表的relation做出如下的设置：

同时我们为Log的数据定义下面的一个strongly typed dataset：AuditLoggingDataSet。该Dataset中只包含一个Table: T_AUDIT_LOG。我们之所以没有定义T_AUDIT_LOG_DETAIL是因为T_AUDIT_LOG_DETAIL中的数据是通过trigger添加的，我们同过程序只需要在主表中添加总体信息就可以了。

三、定义用于Audit log的helper class：AuditLoggingHelper

下面是所有AuditLoggingHelper所有的Code，很简单。我分别定义了一个public的property：AuditLoggingData。其类型为我们上面定义的strongly typed dataset：AuditLoggingDataSet。还定义了一个Public 的方法AuditLog向AuditLoggingData中添加Log信息，并返回一个Guid用以标识将要执行的transaction。我管这个Guid为Transaction no。

using System;
using System.Collections.Generic;
using System.Text;

namespace Artech.AuditLogging.ConsoleApp
{
    public class AuditLoggingHelper
    {
        private AuditLoggingDataSet _auditLoggingData;

        /**//// <summary>
        /// A strongly typed dataset to used to store the general auditoing inforamtion. 
        /// </summary>
        public AuditLoggingDataSet AuditLoggingData
        {
            get { return _auditLoggingData; }
            set { _auditLoggingData = value; }
        }

        /**//// <summary>
        /// Log the general auditoing information according with the current transaction.
        /// </summary>
        /// <returns>A guid which identifies uniquely a transaction</returns>
        public Guid AuditLog()
        {
            if (this._auditLoggingData == null)
            {
                this._auditLoggingData = new AuditLoggingDataSet();
            }

            Guid transactionNo = Guid.NewGuid();
            AuditLoggingDataSet.T_AUDIT_LOGRow auditRow= this._auditLoggingData.T_AUDIT_LOG.NewT_AUDIT_LOGRow();

            auditRow.BeginEdit();
            auditRow.TRANSACTION_NO = transactionNo.ToString();
            //TODO: The user id is generally the account of the current login user.
            auditRow.USER_ID = "testUser";
            auditRow.OPERATION_DATE = DateTime.Now;
            auditRow.EndEdit();

            this._auditLoggingData.T_AUDIT_LOG.AddT_AUDIT_LOGRow(auditRow);

            return transactionNo;
        }
    }
}

四、定义stored procedure和trigger

为了较为真实地贴近我们现实的开发， 本Sample的所有Data access操作（除了data retrieval外）均采用stored procedure。通过所有需要进行Log的详细地信息都是通过Trigger来添加的。所有的stored procedure通过这里来查看，所有的trigger通过这里查看。

五：模拟Insert操作

我们先清空所有的Log数据，通过下面的方法添加一个新的Order。

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;

namespace Artech.AuditLogging.ConsoleApp
{
    class Program
    {
        static string USER_ID = "testUser";

        static void Main(string[] args)
        {
            AddOrderData();
            Console.WriteLine("Operation completes!");
            Console.Read();
        }

        static void UpdateCommonField(DataRow row)
        {
            row["LAST_UPDATED_BY"] = USER_ID;
            row["LAST_UPDATED_ON"] = DateTime.Now;
            if (row.RowState == DataRowState.Detached || row.RowState == DataRowState.Added)
            {
                row["CREATED_BY"] = USER_ID;
                row["CREATED_ON"] = DateTime.Now;
            }
        }  

        
        static void AddOrderData()
        {
            AuditLoggingHelper auditLoggingHelper = new AuditLoggingHelper();
            Guid transactionNo = auditLoggingHelper.AuditLog();

            //Add an order item
            OrderDataSet orderData = new OrderDataSet();
            OrderDataSet.T_ORDERRow orderRow = orderData.T_ORDER.NewT_ORDERRow();
            orderRow.BeginEdit();
            orderRow.ORDER_DATE = DateTime.Today;
            orderRow.SUPPLIER = "HP Corporation";
            UpdateCommonField(orderRow);
            orderRow.TRANSACTION_NO = transactionNo.ToString();
            orderRow.EndEdit();
            orderData.T_ORDER.AddT_ORDERRow(orderRow);

            //Add two order detail items.
            OrderDataSet.T_ORDER_DETAILRow orderDetailRow = orderData.T_ORDER_DETAIL.NewT_ORDER_DETAILRow();
            orderDetailRow.BeginEdit();
            orderDetailRow.ORDER_ID = orderRow.ORDER_ID;
            orderDetailRow.PRODUCT_ID = 1;
            orderDetailRow.PRODUCT_NAME = "HP Printer";
            orderDetailRow.UNIT_PRICE = 3000;
            orderDetailRow.QUANTITY = 2;
            UpdateCommonField(orderDetailRow);
            orderDetailRow.TRANSACTION_NO = transactionNo.ToString();
            orderDetailRow.EndEdit();
            orderData.T_ORDER_DETAIL.AddT_ORDER_DETAILRow(orderDetailRow);

            orderDetailRow = orderData.T_ORDER_DETAIL.NewT_ORDER_DETAILRow();
            orderDetailRow.BeginEdit();
            orderDetailRow.ORDER_ID = orderRow.ORDER_ID;
            orderDetailRow.PRODUCT_ID = 2;
            orderDetailRow.PRODUCT_NAME = "HP PC";
            orderDetailRow.UNIT_PRICE = 3400;
            orderDetailRow.QUANTITY = 22;
            UpdateCommonField(orderDetailRow);
            orderDetailRow.TRANSACTION_NO = transactionNo.ToString();
            orderDetailRow.EndEdit();
            orderData.T_ORDER_DETAIL.AddT_ORDER_DETAILRow(orderDetailRow);

            using (DataAccessHelper dataAccessHelper = new DataAccessHelper())
            {
                dataAccessHelper.BeginTransaction();
                try
                {
                    dataAccessHelper.UpdateData(auditLoggingHelper.AuditLoggingData.T_AUDIT_LOG);
                    dataAccessHelper.UpdateData(orderData.T_ORDER);
                    dataAccessHelper.UpdateData(orderData.T_ORDER_DETAIL);
                    dataAccessHelper.Commit();
                }
                catch(Exception ex)
                {
                    dataAccessHelper.Rollback();
                    Console.WriteLine(ex.Message);
                }
            }
        }
    }
}

我们来看看T_AUDIT_LOG的记录：

T_AUDIT_LOG_DETAIL的记录

DATA_CHANGE的data分别为下面3段XML。

<dataChange>
  <after order_id="33" order_date="Apr 23 2007 12:00AM" supplier="HP Corporation" />
</dataChange>

<dataChange>
  <after order_id="33" product_id="1" product_name="HP Printer" unit_price="3000.00" quantity="2" />
</dataChange>

<dataChange>
  <after order_id="33" product_id="2" product_name="HP PC" unit_price="3400.00" quantity="22" />
</dataChange>

六、模拟Update操作

定义新的方法UpdateOrderData修改我们刚刚添加的Order记录：

    static void UpdateOrderData()
        {
            OrderDataSet orderData = GetAllOrderData();
            AuditLoggingHelper auditLoggingHelper = new AuditLoggingHelper();
            Guid transactionNo = auditLoggingHelper.AuditLog();

            OrderDataSet.T_ORDERRow orderRow = orderData.T_ORDER[0];
            orderRow.ORDER_DATE = new DateTime(2005, 1, 1);
            orderRow.SUPPLIER = "Dell Corporation";
            orderRow.TRANSACTION_NO  = transactionNo.ToString();
            UpdateCommonField(orderRow);

            OrderDataSet.T_ORDER_DETAILRow orderDetailRow = orderData.T_ORDER_DETAIL[0];
            orderDetailRow.PRODUCT_ID = 3;
            orderDetailRow.PRODUCT_NAME = "Workstation";
            orderDetailRow.UNIT_PRICE = 10000;
            orderDetailRow.QUANTITY = 1;
            orderDetailRow.TRANSACTION_NO  = transactionNo.ToString();
            UpdateCommonField(orderDetailRow);

            using (DataAccessHelper dataAccessHelper = new DataAccessHelper())
            {                
                dataAccessHelper.BeginTransaction();
                try
                {
                    dataAccessHelper.UpdateData(auditLoggingHelper.AuditLoggingData.T_AUDIT_LOG);
                    dataAccessHelper.UpdateData(orderData.T_ORDER);
                    dataAccessHelper.UpdateData(orderData.T_ORDER_DETAIL);
                    dataAccessHelper.Commit();
                }
                catch (Exception ex)
                {
                    dataAccessHelper.Rollback();
                    Console.WriteLine(ex.Message);
                }
            }            
        }

执行上面的方法，然后查看我们Log表的记录。

 

两条Update记录对应的DATA_CHANGE字段的XML分别为：

<dataChange>
  <before order_id="33" order_date="Apr 23 2007 12:00AM" supplier="HP Corporation" />
  <after order_id="33" order_date="Jan  1 2005 12:00AM" supplier="Dell Corporation" />
</dataChange>

<dataChange>
  <before order_id="33" product_id="1" product_name="HP Printer" unit_price="3000.00" quantity="2" />
  <after order_id="33" product_id="1" product_name="Workstation" unit_price="10000.00" quantity="1" />
</dataChange>

七、模拟Delete操作

定于DeleteOrderData方法delete掉我们添加的Order记录：

static void DeleteOrderData()
        {
            OrderDataSet orderData = GetAllOrderData();
            AuditLoggingHelper auditLoggingHelper = new AuditLoggingHelper();
            Guid transactionNo = auditLoggingHelper.AuditLog();

            //Delete two order detail items.
            OrderDataSet.T_ORDER_DETAILRow orderDetailRow = orderData.T_ORDER_DETAIL[0];
            orderDetailRow.TRANSACTION_NO = transactionNo.ToString();
            orderDetailRow.AcceptChanges();
            orderDetailRow.Delete();

            orderDetailRow = orderData.T_ORDER_DETAIL[1];
            orderDetailRow.TRANSACTION_NO = transactionNo.ToString();
            orderDetailRow.AcceptChanges();
            orderDetailRow.Delete();

            //Delete the order item.
            OrderDataSet.T_ORDERRow orderRow = orderData.T_ORDER[0];
            orderRow.TRANSACTION_NO = transactionNo.ToString();
            orderRow.AcceptChanges();
            orderRow.Delete();

            using (DataAccessHelper dataAccessHelper = new DataAccessHelper())
            {
                dataAccessHelper.BeginTransaction();
                try
                {
                    dataAccessHelper.UpdateData(auditLoggingHelper.AuditLoggingData.T_AUDIT_LOG);
                    dataAccessHelper.UpdateData(orderData.T_ORDER_DETAIL);
                    dataAccessHelper.UpdateData(orderData.T_ORDER);

                    dataAccessHelper.Commit();
                }
                catch (Exception ex)
                {
                    dataAccessHelper.Rollback();
                    Console.WriteLine(ex.Message);
                }
            }
        }

执行上面的方法，然后查看我们Log表的记录。

三条Delete记录对应的DATA_CHANGE字段的XML分别为：

<dataChange>
  <before order_id="33" product_id="1" product_name="Workstation" unit_price="10000.00" quantity="1" />
</dataChange>

<dataChange>
  <before order_id="33" product_id="2" product_name="HP PC" unit_price="3400.00" quantity="22" />
</dataChange>

<dataChange>
  <before order_id="33" order_date="Jan  1 2005 12:00AM" supplier="Dell Corporation" />
</dataChange>