在自己的数据库里创建内置表来处理异常(译)

在自己的数据库里创建内置表来处理异常
翻译自：http://rickie.cnblogs.com/
Apr. 24, 2006
本文将讲述在使用 Enterprise Library 2.0 中的 Logging Application block 时，如何在自己建立的数据库里创建内置的表来记录异常，而不是使用独立的一个日志数据库。同时，使用 Logging 和 usp_Logging 来分别做为表和存储过程的前缀，以避免和已经存在的库中的表和存储过程冲突。

完成这个步骤大体分以下三个步骤：
1. 在已经存在的库里建表
下面的 SQL 脚本在已经存在的库里创建3个表, Logging_Category, Logging_CategoryLog 和 Logging_Log.
CREATE TABLE [dbo].[Logging_Category](
[CategoryID] [int] IDENTITY(1,1) NOT NULL,
[CategoryName] [nvarchar](64) NOT NULL,
CONSTRAINT [PK_Categories] PRIMARY KEY CLUSTERED
(
[CategoryID] ASC
) ON [PRIMARY]
) ON [PRIMARY]

CREATE TABLE [dbo].[Logging_CategoryLog](
[CategoryLogID] [int] IDENTITY(1,1) NOT NULL,
[CategoryID] [int] NOT NULL,
[LogID] [int] NOT NULL,
CONSTRAINT [PK_CategoryLog] PRIMARY KEY CLUSTERED
(
[CategoryLogID] ASC
) ON [PRIMARY]
) ON [PRIMARY]

CREATE TABLE [dbo].[Logging_Log](
[LogID] [int] IDENTITY(1,1) NOT NULL,
[EventID] [int] NULL,
[Priority] [int] NOT NULL,
[Severity] [nvarchar](32) NOT NULL,
[Title] [nvarchar](256) NOT NULL,
[Timestamp] [datetime] NOT NULL,
[MachineName] [nvarchar](32) NOT NULL,
[AppDomainName] [nvarchar](512) NOT NULL,
[ProcessID] [nvarchar](256) NOT NULL,
[ProcessName] [nvarchar](512) NOT NULL,
[ThreadName] [nvarchar](512) NULL,
[Win32ThreadId] [nvarchar](128) NULL,
[Message] [nvarchar](1500) NULL,
[FormattedMessage] [ntext] NULL,
CONSTRAINT [PK_Log] PRIMARY KEY CLUSTERED
(
[LogID] ASC
) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
2. 在已经存在的库里建存储过程
下面的 SQL 脚本在上面的表里创建 4 个存储过程：usp_Logging_InsertCategoryLog, usp_Logging_AddCategory, usp_Logging_ClearLogs 和usp_Logging_WriteLog.

CREATE PROCEDURE usp_Logging_InsertCategoryLog
@CategoryID INT,
@LogID INT
AS
BEGIN
SET NOCOUNT ON;

DECLARE @CatLogID INT
SELECT @CatLogID FROM Logging_CategoryLog WHERE CategoryID=@CategoryID and LogID = @LogID
IF @CatLogID IS NULL
BEGIN
INSERT INTO Logging_CategoryLog (CategoryID, LogID) VALUES(@CategoryID, @LogID)
RETURN @@IDENTITY
END
ELSE RETURN @CatLogID
END

CREATE PROCEDURE [dbo].[usp_Logging_AddCategory]
-- Add the parameters for the function here
@CategoryName nvarchar(64),
@LogID int
AS
BEGIN
SET NOCOUNT ON;
DECLARE @CatID INT
SELECT @CatID = CategoryID FROM Logging_Category WHERE CategoryName = @CategoryName
IF @CatID IS NULL
BEGIN
INSERT INTO Logging_Category (CategoryName) VALUES(@CategoryName)
SELECT @CatID = @@IDENTITY
END

EXEC usp_Logging_InsertCategoryLog @CatID, @LogID

RETURN @CatID
END

CREATE PROCEDURE usp_Logging_ClearLogs
AS
BEGIN
SET NOCOUNT ON;

DELETE FROM Logging_CategoryLog
DELETE FROM Logging_Log
DELETE FROM Logging_Category
END

CREATE PROCEDURE [dbo].[usp_Logging_WriteLog]
(
@EventID int,
@Priority int,
@Severity nvarchar(32),
@Title nvarchar(256),
@Timestamp datetime,
@MachineName nvarchar(32),
@AppDomainName nvarchar(512),
@ProcessID nvarchar(256),
@ProcessName nvarchar(512),
@ThreadName nvarchar(512),
@Win32ThreadId nvarchar(128),
@Message nvarchar(1500),
@FormattedMessage ntext,
@LogId int OUTPUT
)
AS

INSERT INTO [Logging_Log] (
EventID,
Priority,
Severity,
Title,
[Timestamp],
MachineName,
AppDomainName,
ProcessID,
ProcessName,
ThreadName,
Win32ThreadId,
Message,
FormattedMessage
)
VALUES (
@EventID,
@Priority,
@Severity,
@Title,
@Timestamp,
@MachineName,
@AppDomainName,
@ProcessID,
@ProcessName,
@ThreadName,
@Win32ThreadId,
@Message,
@FormattedMessage)

SET @LogID = @@IDENTITY
RETURN @LogID

3. 配置app.config/web.config来使用新的存储过程
正因为进行了上面的改变，我们需要改变配置 logging application block 的默认值和存储过程的名字。只需要改变两个属性：AddCategoryStoredProcdure 和 WriteLogStoredProcedureName。可以通过下面的图示在你的应用中改变这两个值。