Question

我们正在考虑起诉一些SQL CLR触发器来填充某些表的审计日志，我知道如何在服务器中注册CLR程序集和触发器，当我知道要查找哪些列以及是否必须只需在审计日志表中插入新记录。

现在我们希望它独立于被监视的表模式，这样我们就不需要在添加或重命名到源表的每个新列上编辑和重新部署触发器，I我希望在我的审计表中保留一些简单的内容，例如包含更改快照的n XML列，如：

<AuditEntry ObjectName='TableName' ObjectId='1'>
    <Field='Firstname'>
        <OldValue>David</OldValue>
        <NewValue>Davide</NewValue>
    </Field>
    <Field='Email'>
        <OldValue/>
        <NewValue>aaa.b@gmail.com</NewValue>
    </Field>
</AuditEntry>

这个XML只是一个例子，我只需要了解如何编写我的触发器C＃代码，这样就可以通过字段获取旧值和新值来比较旧行和新行字段然后我知道如何将其转储到XML文档。

非常感谢，的Davide。

Answer 1

我做了一些测试，我能够自己解决这个问题，这是为了分享它的全部故事; - ）

1） .NET SQL CLR触发器，仅触发两个表的触发器，唯一的假设是监视的表具有名为 Id <的标识列/ p>

using System.Data.SqlClient;
using System.Xml;
using Microsoft.SqlServer.Server;

namespace Axis.CLR.SampleObjects
{
    using System;
    using System.Data;
    using System.Data.SqlTypes;
    using System.Text;

    public partial class AuditTrigger
    {
        public const string GetTableContextStatement =
            "SELECT object_name(resource_associated_entity_id) FROM sys.dm_tran_locks WHERE request_session_id = @@spid and resource_type = 'OBJECT'";

        [SqlTrigger(Name = "UserNameAudit", Target = "Users", Event = "FOR INSERT")]
        public static void UserNameAudit()
        {
            SqlTriggerContext triggContext = SqlContext.TriggerContext;

            //SqlPipe sqlP = SqlContext.Pipe;

            using (SqlConnection conn = new SqlConnection("context connection=true"))
            using (SqlCommand sqlComm = conn.CreateCommand())
            {
                conn.Open();

                // Gets a reference to the affected table name
                string tableName = string.Empty;
                using (SqlCommand cmd = new SqlCommand(GetTableContextStatement, conn))
                {
                    tableName = cmd.ExecuteScalar().ToString();
                }

                // STORING INSERT AUDIT

                if (triggContext.TriggerAction == TriggerAction.Insert)
                {
                    #region handling INSERT action

                    sqlComm.CommandText = "SELECT * from INSERTED";
                    var reader = sqlComm.ExecuteReader();

                    if (reader.Read())
                    {
                        XmlDocument finalDocument = new XmlDocument();

                        XmlNode rootElement = finalDocument.CreateNode(XmlNodeType.Element, tableName, string.Empty);

                        XmlAttribute newAttribute = finalDocument.CreateAttribute("Id");
                        newAttribute.Value = reader.GetInt64(reader.GetOrdinal("Id")).ToString();
                        rootElement.Attributes.Append(newAttribute);

                        newAttribute = finalDocument.CreateAttribute("Operation");
                        newAttribute.Value = "INSERT";
                        rootElement.Attributes.Append(newAttribute);

                        finalDocument.AppendChild(rootElement);

                        XmlNode createdElement = finalDocument.CreateNode(XmlNodeType.Element, "Fields", string.Empty);

                        for (int i = 0; i < reader.FieldCount; i++)
                        {
                            XmlNode fieldElement = finalDocument.CreateNode(XmlNodeType.Element, reader.GetName(i), string.Empty);

                            if (reader.IsDBNull(i))
                            {
                                fieldElement.InnerText = "NULL";
                            }
                            else
                            {
                                fieldElement.InnerText = reader.GetValue(i).ToString();
                            }

                            createdElement.AppendChild(fieldElement);
                        }

                        // Node was added
                        rootElement.AppendChild(createdElement);

                        // Adds the Audit

                        sqlComm.CommandText = "[dbo].[AddAuditTrail]";
                        sqlComm.CommandType = CommandType.StoredProcedure;

                        SqlParameter xmlParamA = new SqlParameter("@ObjectId", SqlDbType.BigInt);
                        xmlParamA.Value = reader.GetInt64(reader.GetOrdinal("Id"));
                        sqlComm.Parameters.Add(xmlParamA);

                        reader.Close();

                        sqlComm.Parameters.AddWithValue("@ObjectName", tableName);

                        SqlParameter xmlParamB = new SqlParameter("@TraceXML", SqlDbType.Xml);
                        xmlParamB.Value = new SqlXml(new XmlTextReader(finalDocument.OuterXml, XmlNodeType.Document, null));
                        sqlComm.Parameters.Add(xmlParamB);

                        sqlComm.Parameters.AddWithValue("@AuditType", "INSERT");

                        sqlComm.ExecuteNonQuery();

                        //sqlP.Send(string.Format("Generated AFTER INSERT XML is: '{0}'", finalDocument.OuterXml));
                    }

                    #endregion handling INSERT action
                }
                else if (triggContext.TriggerAction == TriggerAction.Update)
                {
                    #region handling UPDATE action

                    DataSet values = new DataSet();
                    SqlDataAdapter adapter = new SqlDataAdapter(sqlComm);

                    sqlComm.CommandText = "SELECT * from INSERTED";
                    adapter.Fill(values, "INSERTED");

                    sqlComm.CommandText = "SELECT * from DELETED";
                    adapter.Fill(values, "DELETED");

                    StringBuilder builder = new StringBuilder();

                    builder.Append("<Fields>");

                    int recordId = 0;

                    for (int i = 0; i < values.Tables["INSERTED"].Columns.Count; i++)
                    {
                        string colName = values.Tables["INSERTED"].Columns[i].ColumnName;

                        if (colName.ToLower().Equals("id"))
                        {
                            recordId = Convert.ToInt32(values.Tables["DELETED"].Rows[0][i]);

                            builder.AppendFormat("<Id value='{0}' />", recordId);
                        }

                        // if both nulls or both the same, no audit needed...

                        if (values.Tables["INSERTED"].Rows[0].IsNull(i) && values.Tables["DELETED"].Rows[0].IsNull(i))
                        {
                            continue;
                        }

                        if (values.Tables["INSERTED"].Rows[0][i].Equals(values.Tables["DELETED"].Rows[0][i]))
                        {
                            continue;
                        }

                        builder.AppendFormat("<{0}>", colName);

                        // DUMPING OLD VALUE
                        builder.Append("<OldValue>");

                        if (values.Tables["DELETED"].Rows[0].IsNull(i))
                        {
                            builder.Append("NULL");
                        }
                        else
                        {
                            builder.Append(values.Tables["DELETED"].Rows[0][i]);
                        }

                        builder.Append("</OldValue>");

                        // DUMPING NEW VALUE
                        builder.Append("<NewValue>");

                        if (values.Tables["INSERTED"].Rows[0].IsNull(i))
                        {
                            builder.Append("NULL");
                        }
                        else
                        {
                            builder.Append(values.Tables["INSERTED"].Rows[0][i]);
                        }

                        builder.Append("</NewValue>");

                        builder.AppendFormat("</{0}>", colName);
                    }

                    builder.Append("</Fields>");

                    builder.Insert(0, string.Format("<{0} Id='{1}' Operation='{2}'>", tableName, recordId, "UPDATE"));
                    builder.AppendFormat("</{0}>", tableName);

                    // Adds the Audit

                    sqlComm.CommandText = "[dbo].[AddAuditTrail]";
                    sqlComm.CommandType = CommandType.StoredProcedure;

                    SqlParameter xmlParamA = new SqlParameter("@ObjectId", SqlDbType.BigInt);
                    xmlParamA.Value = recordId;
                    sqlComm.Parameters.Add(xmlParamA);

                    sqlComm.Parameters.AddWithValue("@ObjectName", tableName);

                    SqlParameter xmlParamB = new SqlParameter("@TraceXML", SqlDbType.Xml);
                    xmlParamB.Value = new SqlXml(new XmlTextReader(builder.ToString(), XmlNodeType.Document, null));
                    sqlComm.Parameters.Add(xmlParamB);

                    sqlComm.Parameters.AddWithValue("@AuditType", "UPDATE");

                    sqlComm.ExecuteNonQuery();

                    //sqlP.Send(string.Format("Generated AFTER UPDATE XML is: '{0}'", builder.ToString()));

                    #endregion handling UPDATE action
                }
            }
        }
    }
}

2）这里我用来在sql服务器上注册触发器并将其链接到两个不同的表（用户和产品）的SQL代码，只有1个CLR触发器但在SQL服务器中使用CLR创建两个触发器作为外部触发器，每个触发器用于每个表

USE [Axis_Davide]
GO

BEGIN TRANSACTION SCRIPT
---------------------------------

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'trAuditTriggerA') AND type in (N'TA'))
BEGIN
    DROP TRIGGER [dbo].[trAuditTriggerA]
        PRINT('Trigger A was removed');
END

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'trAuditTriggerB') AND type in (N'TA'))
BEGIN
    DROP TRIGGER [dbo].[trAuditTriggerB]
        PRINT('Trigger B was removed');
END


IF EXISTS (SELECT * FROM sys.assemblies asms WHERE asms.name = N'Axis.CLR.SampleObjects' and is_user_defined = 1)
BEGIN
    DROP ASSEMBLY [Axis.CLR.SampleObjects]
    PRINT('Assembly was removed');
END

CREATE ASSEMBLY [Axis.CLR.SampleObjects]
AUTHORIZATION [dbo]
FROM 'C:\Axis\SQLCLR_Samples\Axis.CLR.SampleObjects.dll'
WITH PERMISSION_SET = SAFE
PRINT('Assembly was created');

EXEC('CREATE TRIGGER trAuditTriggerA ON [dbo].[Users] AFTER INSERT, UPDATE AS EXTERNAL NAME [Axis.CLR.SampleObjects].[Axis.CLR.SampleObjects.AuditTrigger].[UserNameAudit]')
PRINT('Trigger A was created');

EXEC('CREATE TRIGGER trAuditTriggerB ON [dbo].[Products] AFTER INSERT, UPDATE AS EXTERNAL NAME [Axis.CLR.SampleObjects].[Axis.CLR.SampleObjects.AuditTrigger].[UserNameAudit]')
PRINT('Trigger B was created');

---------------------------------
COMMIT TRANSACTION SCRIPT

3）这里是我的审计表的创建声明

CREATE TABLE [dbo].[AuditTrail]
(
    [Id] [bigint] IDENTITY(1,1) NOT NULL,
    [AuditDate] [datetime2](7) NOT NULL,
    [UserName] [nvarchar](64) NOT NULL,
    [ObjectId] [bigint] NOT NULL,
    [ObjectName] [nvarchar](128) NOT NULL,
    [TraceXML] [xml] NOT NULL,
    [TraceSize] [int] NOT NULL,
    [AuditType] [nvarchar](16) NOT NULL,
 CONSTRAINT [PK_AuditTrail] PRIMARY KEY CLUSTERED ( [Id] ASC )
)
GO

ALTER TABLE [dbo].[AuditTrail] ADD  CONSTRAINT [DF_AuditTrail_AuditDate]  DEFAULT (sysutcdatetime()) FOR [AuditDate]
GO

ALTER TABLE [dbo].[AuditTrail] ADD  CONSTRAINT [DF_AuditTrail_UserName]  DEFAULT (suser_sname()) FOR [UserName]
GO

4）这里触发器调用的存储过程在每次插入/更新时添加新的审核记录

CREATE PROCEDURE [dbo].[AddAuditTrail]
    @ObjectId bigint, 
    @ObjectName nvarchar(128),
    @TraceXML xml,
    @AuditType nvarchar(16)
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    INSERT INTO [dbo].[AuditTrail] ([ObjectId], [ObjectName], [TraceXML], [TraceSize], [AuditType])
        VALUES (@ObjectId, @ObjectName, @TraceXML, DATALENGTH(@TraceXML), @AuditType)
END
GO

5）对于INSERT和UPDATE

，我的审核表内容如下所示

<Users Id="51" Operation="INSERT">
  <Fields>
    <UserName>Davide</UserName>
    <Pass>Test</Pass>
    <Id>51</Id>
    <Email>NULL</Email>
  </Fields>
</Users>

<Users Id="51" Operation="UPDATE">
  <Fields>
    <Id value="51" />
    <Email>
      <OldValue>NULL</OldValue>
      <NewValue>@</NewValue>
    </Email>
  </Fields>
</Users>

如何比较CLR插入和更新触发器中的旧字段值和新字段值

1 个答案: