Esempio CLR Transactions
In questo esempio viene illustrato il controllo delle transazioni tramite le API gestite dello spazio dei nomi System.Transactions . In particolare, viene utilizzata la classe System.Transactions.TransactionScope per stabilire un limite della transazione al fine di garantire che i valori delle scorte non vengano rettificati a meno che siano presenti scorte sufficienti per soddisfare la richiesta. Se le scorte sono sufficienti, si garantisce che il trasferimento dal magazzino o da una posizione a un'altra avvenga in modo atomico. La registrazione automatica in una transazione distribuita è illustrata registrando le modifiche nell'inventario in un database di controllo archiviato in un'istanza separata di SQL Server.
Prerequisiti
Per creare ed eseguire questo progetto, è necessario installare il software seguente:
SQL Server o SQL Server Express. È possibile ottenere SQL Server Express gratuitamente dal sito Web documentazione e esempi di SQL Server Express
Database AdventureWorks disponibile nel sito Web di SQL Server Developer
.NET Framework SDK 2.0 o versione successiva oppure Microsoft Visual Studio 2005 o versione successiva. .NET Framework SDK è disponibile gratuitamente.
È necessario inoltre che siano soddisfatte le condizioni seguenti:
L'istanza SQL Server usata deve avere l'integrazione CLR abilitata.
Per abilitare l'integrazione con CLR, effettuare le operazioni seguenti:
Abilitazione dell'integrazione con CLR
- Eseguire i comandi Transact-SQL seguenti:
sp_configure 'clr enabled', 1GORECONFIGUREGONota
Per abilitare CLR, è necessario disporre dell'autorizzazione
ALTER SETTINGSa livello di server, che viene assegnata implicitamente ai membri dei ruoli predefiniti del serversysadmineserveradmin.Il database AdventureWorks deve essere installato nell'istanza di SQL Server in uso.
Se non si è un amministratore per l'istanza di SQL Server usata, è necessario disporre di un amministratore che concede l'autorizzazione CreateAssembly per completare l'installazione.
Compilazione dell'esempio
Creare ed eseguire l'esempio tramite le istruzioni seguenti:
Aprire un prompt dei comandi di .NET Framework o Visual Studio.
Se necessario, creare una directory per l'esempio. Per questo esempio verrà utilizzata la directory C:\MySample.
Poiché per questo esempio è necessario un assembly firmato, creare una chiave asimmetrica digitando il comando:
sn -k SampleKey.snkCompilare il codice di esempio dal prompt della riga di comando eseguendo una delle istruzioni seguenti, a seconda del linguaggio scelto.
Vbc /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\v3.5\System.Core.dll","C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\v3.5\System.Data.DataSetExtensions.dll","C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll","C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll","C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Transactions.dll","C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Xml.dll" /keyfile:Key.snk /target:Library /out:Transaction.dll InventoryMover.vbCsc /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Transactions.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Xml.dll /keyfile:key.snk /out:Transaction.dll /target:library InventoryMover.cs
Copiare il codice di installazione Transact-SQL in un file e salvarlo come
install.sqlnella directory di esempio.Distribuire l'assembly e la stored procedure eseguendo
sqlcmd -E -I -i install.sql -v root = "C:\MySample\"
Copiare il codice di installazione del database Transact-SQL in un file e salvarlo come
installDB.sqlnella directory di esempio.Installare il database di controllo eseguendo
Sqlcmd -S server_name [ \instance_name ] -E -I -i installDB.sql
con valori appropriati per l'istanza e il server.
Copiare lo script di comando di test Transact-SQL in un file e salvarlo come
test.sqlnella directory di esempio.Eseguire lo script di test con il comando seguente
sqlcmd -E -I -i test.sql
Copiare lo script di pulizia del database Transact-SQL in un file e salvarlo come
cleanupDB.sqlnella directory di esempio.Eseguire lo script con il comando seguente
Sqlcmd -S server_name [ \instance_name ] -E -I -i cleanup.sqlcon valori appropriati per l'istanza e il server.
Copiare lo script di pulizia Transact-SQL in un file e salvarlo come
cleanup.sqlnella directory di esempio.Eseguire lo script con il comando seguente
sqlcmd -E -I -i cleanup.sql
Codice di esempio
Di seguito sono illustrati i listati di codice per l'esempio.
C#
using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlTypes;
using System.Data.SqlClient;
using System.Transactions;
using Microsoft.SqlServer.Server;
using System.Security.Principal;
public static class InventoryMover
{
const string contextConnectionString = "context connection=true";
// **********
// Important: Change this connection string to refer to a server other than the one
// you have installed the AdventureWorks database. This sample demonstrates
// two-phase commit across multiple servers, and loopback to the same server is not
// permitted from CLR integrated based stored procedures.
// **********
const string auditConnectionString = "server=<YourServer>; database=InventoryAudit; user=<YourUser>; password=<YourPassword>";
[SqlMethod(DataAccess = DataAccessKind.Read, IsMutator = true)]
public static void ExecuteTransfer(int productID, short fromLocationID,
short toLocationID, short quantityToTransfer)
{
// Establish bounds of the transaction
using (TransactionScope transScope = new TransactionScope())
{
using (SqlConnection adventureworksConnection = new
SqlConnection(contextConnectionString))
{
// Opening adventureworksConnection automatically enlists it in the
// TransactionScope as part of the transaction.
adventureworksConnection.Open();
SqlCommand checkCommand = adventureworksConnection.CreateCommand();
checkCommand.CommandText = "SELECT TOP 1 Quantity"
+ " FROM Production.ProductInventory WITH (REPEATABLEREAD)"
+ " WHERE ProductID = @ProductID AND LocationID = @LocationID;";
checkCommand.Parameters.Add("@ProductID", SqlDbType.Int);
checkCommand.Parameters[0].Value = productID;
checkCommand.Parameters.Add("@LocationID", SqlDbType.Int);
checkCommand.Parameters[1].Value = fromLocationID;
object result = checkCommand.ExecuteScalar();
short availableQuantity = (short)result;
if (availableQuantity < quantityToTransfer)
//It would be better to throw a custom error, and in some cases to actually
//RAISERROR. Also, it would be better to map product IDs and location IDs to
//names for the error message.
throw new ArgumentOutOfRangeException("quantityToTransfer",
string.Format("Attempt to transfer {0} of product {1} from"
+ " location {2} but only {3} is available.",
quantityToTransfer, productID, fromLocationID,
availableQuantity));
//Remove inventory count from source
SqlCommand reduceCommand = adventureworksConnection.CreateCommand();
reduceCommand.CommandText = "UPDATE Production.ProductInventory"
+ " SET Quantity = Quantity - @QuantityToTransfer"
+ " WHERE ProductID = @ProductID AND LocationID = @LocationID;";
reduceCommand.Parameters.Add("@ProductID", SqlDbType.Int);
reduceCommand.Parameters[0].Value = productID;
reduceCommand.Parameters.Add("@LocationID", SqlDbType.SmallInt);
reduceCommand.Parameters[1].Value = fromLocationID;
reduceCommand.Parameters.Add("@QuantityToTransfer", SqlDbType.SmallInt);
reduceCommand.Parameters[2].Value = quantityToTransfer;
reduceCommand.ExecuteNonQuery();
//Increate inventory count at destination
SqlCommand increaseCommand = adventureworksConnection.CreateCommand();
increaseCommand.CommandText = "UPDATE Production.ProductInventory"
+ " SET Quantity = Quantity + @QuantityToTransfer"
+ " WHERE ProductID = @ProductID AND LocationID = @LocationID;";
increaseCommand.Parameters.Add("@ProductID", SqlDbType.Int);
increaseCommand.Parameters[0].Value = productID;
increaseCommand.Parameters.Add("@LocationID", SqlDbType.SmallInt);
increaseCommand.Parameters[1].Value = toLocationID;
increaseCommand.Parameters.Add("@QuantityToTransfer", SqlDbType.SmallInt);
increaseCommand.Parameters[2].Value = quantityToTransfer;
increaseCommand.ExecuteNonQuery();
// Create an audit trail of the inventory transfer. We must impersonate the
// client credentials in order for this to work. Otherwise we'd have to
// set up security for the machine account.
// SqlConnection auditConnection = adventureworksConnection;
using (SqlConnection auditConnection = new SqlConnection(auditConnectionString))
{
SqlCommand auditCommand = auditConnection.CreateCommand();
auditCommand.CommandText = "INSERT InventoryChange "
+ " (ProductID, FromLocationID, ToLocationID, Quantity) "
+ " VALUES (@ProductID, @FromLocationID, @ToLocationID, @Quantity);";
auditCommand.Parameters.Add("@ProductID", SqlDbType.Int);
auditCommand.Parameters[0].Value = productID;
auditCommand.Parameters.Add("@FromLocationID", SqlDbType.SmallInt);
auditCommand.Parameters[1].Value = fromLocationID;
auditCommand.Parameters.Add("@ToLocationID", SqlDbType.SmallInt);
auditCommand.Parameters[2].Value = toLocationID;
auditCommand.Parameters.Add("@Quantity", SqlDbType.SmallInt);
auditCommand.Parameters[3].Value = quantityToTransfer;
// Opening auditConnection automatically enlists it in the
// TransactionScope as part of the transaction.
auditConnection.Open();
auditCommand.ExecuteNonQuery();
}
}
// The Complete method commits the transaction.
transScope.Complete();
}
}
}
Visual Basic
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports System.Data
Imports System.Data.SqlTypes
Imports System.Data.SqlClient
Imports System.Transactions
Imports Microsoft.SqlServer.Server
Imports System.Security.Principal
Imports System.Globalization
Public NotInheritable Class InventoryMover
Private Const contextConnectionString As String = "context connection=true"
Private Sub New()
End Sub
' **********
' Important: Change this connection string to refer to a server other than the one
' you have installed the AdventureWorks database. This sample demonstrates
' two-phase commit across multiple servers, and loopback to the same server is not
' permitted from CLR integrated based stored procedures.
' **********
Private Const auditConnectionString As String = "server=<YourServer>; database=InventoryAudit; user=<YourUser>; password=<YourPassword>"
<SqlMethod(DataAccess:=DataAccessKind.Read, IsMutator:=True)> _
Public Shared Sub ExecuteTransfer(ByVal productID As Integer, ByVal fromLocationID As Short, _
ByVal toLocationID As Short, ByVal quantityToTransfer As Short)
' Establish bounds of the transaction
Using transScope As New TransactionScope()
Using adventureworksConnection As New SqlConnection(contextConnectionString)
' Opening adventureworksConnection automatically enlists it in the
' TransactionScope as part of the transaction.
adventureworksConnection.Open()
Dim checkCommand As SqlCommand = adventureworksConnection.CreateCommand()
checkCommand.CommandText = "SELECT TOP 1 Quantity" _
& " FROM Production.ProductInventory WITH (REPEATABLEREAD)" _
& " WHERE ProductID = @ProductID AND LocationID = @LocationID;"
checkCommand.Parameters.Add("@ProductID", SqlDbType.Int)
checkCommand.Parameters(0).Value = productID
checkCommand.Parameters.Add("@LocationID", SqlDbType.Int)
checkCommand.Parameters(1).Value = fromLocationID
Dim result As Object = checkCommand.ExecuteScalar()
Dim availableQuantity As Short = CType(result, Short)
If (availableQuantity < quantityToTransfer) Then
'It would be better to throw a custom error, and in some cases to actually
'RAISERROR. Also, it would be better to map product IDs and location IDs to
'names for the error message.
Throw New ArgumentOutOfRangeException("quantityToTransfer", _
String.Format(CultureInfo.InvariantCulture, "Attempt to transfer {0} of product {1} from" _
& " location {2} but only {3} is available.", _
quantityToTransfer, productID, fromLocationID, _
availableQuantity))
End If
'Remove inventory count from source
Dim reduceCommand As SqlCommand = adventureworksConnection.CreateCommand()
reduceCommand.CommandText = "UPDATE Production.ProductInventory" _
& " SET Quantity = Quantity - @QuantityToTransfer" _
& " WHERE ProductID = @ProductID AND LocationID = @LocationID;"
reduceCommand.Parameters.Add("@ProductID", SqlDbType.Int)
reduceCommand.Parameters(0).Value = productID
reduceCommand.Parameters.Add("@LocationID", SqlDbType.SmallInt)
reduceCommand.Parameters(1).Value = fromLocationID
reduceCommand.Parameters.Add("@QuantityToTransfer", SqlDbType.SmallInt)
reduceCommand.Parameters(2).Value = quantityToTransfer
reduceCommand.ExecuteNonQuery()
'Increate inventory count at destination
Dim increaseCommand As SqlCommand = adventureworksConnection.CreateCommand()
increaseCommand.CommandText = "UPDATE Production.ProductInventory" _
& " SET Quantity = Quantity + @QuantityToTransfer" _
& " WHERE ProductID = @ProductID AND LocationID = @LocationID;"
increaseCommand.Parameters.Add("@ProductID", SqlDbType.Int)
increaseCommand.Parameters(0).Value = productID
increaseCommand.Parameters.Add("@LocationID", SqlDbType.SmallInt)
increaseCommand.Parameters(1).Value = toLocationID
increaseCommand.Parameters.Add("@QuantityToTransfer", SqlDbType.SmallInt)
increaseCommand.Parameters(2).Value = quantityToTransfer
increaseCommand.ExecuteNonQuery()
' Create an audit trail of the inventory transfer. We must impersonate the
' client credentials in order for this to work. Otherwise we'd have to
' set up security for the machine account.
'SqlConnection auditConnection = adventureworksConnection
Using auditConnection As New SqlConnection(auditConnectionString)
Dim auditCommand As SqlCommand = auditConnection.CreateCommand()
auditCommand.CommandText = "INSERT InventoryChange " _
& " (ProductID, FromLocationID, ToLocationID, Quantity) " _
& " VALUES (@ProductID, @FromLocationID, @ToLocationID, @Quantity);"
auditCommand.Parameters.Add("@ProductID", SqlDbType.Int)
auditCommand.Parameters(0).Value = productID
auditCommand.Parameters.Add("@FromLocationID", SqlDbType.SmallInt)
auditCommand.Parameters(1).Value = fromLocationID
auditCommand.Parameters.Add("@ToLocationID", SqlDbType.SmallInt)
auditCommand.Parameters(2).Value = toLocationID
auditCommand.Parameters.Add("@Quantity", SqlDbType.SmallInt)
auditCommand.Parameters(3).Value = quantityToTransfer
' Opening auditConnection automatically enlists it in the
' TransactionScope as part of the transaction.
auditConnection.Open()
auditCommand.ExecuteNonQuery()
End Using
End Using
' The Complete method commits the transaction.
transScope.Complete()
End Using
End Sub
End Class
Si tratta dello script di installazione Transact-SQL (Install.sql), che distribuisce l'assembly e crea la stored procedure nel database.
USE AdventureWorks
GO
-- Drop existing sproc and assembly if any.
IF EXISTS (SELECT * FROM sys.procedures WHERE [name] = 'usp_ExecuteTransfer')
DROP PROCEDURE usp_ExecuteTransfer;
GO
IF EXISTS (SELECT * FROM sys.assemblies WHERE [name] = 'Transaction')
DROP ASSEMBLY [Transaction];
GO
USE master
GO
IF EXISTS (SELECT * FROM sys.server_principals WHERE [name] = 'ExternalSample_Login')
DROP LOGIN ExternalSample_Login;
GO
IF EXISTS (SELECT * FROM sys.asymmetric_keys WHERE [name] = 'ExternalSample_Key')
DROP ASYMMETRIC KEY ExternalSample_Key;
GO
DECLARE @SamplesPath nvarchar(1024)
-- You may need to modify the value of the this variable if you have installed the sample someplace other than the default location.
set @SamplesPath = 'C:\MySample\'
EXEC('CREATE ASYMMETRIC KEY ExternalSample_Key FROM EXECUTABLE FILE = ''' + @SamplesPath + 'Transaction.dll'';');
CREATE LOGIN ExternalSample_Login FROM ASYMMETRIC KEY ExternalSample_Key
GRANT EXTERNAL ACCESS ASSEMBLY TO ExternalSample_Login
GO
USE AdventureWorks
GO
DECLARE @SamplesPath nvarchar(1024)
-- You may need to modify the value of this variable if you have installed the sample someplace other than the default location.
set @SamplesPath = 'C:\MySample\'
-- Add the assembly and CLR integration based stored procedure
CREATE ASSEMBLY [Transaction]
FROM @SamplesPath + 'Transaction.dll'
WITH permission_set = External_Access;
GO
CREATE PROCEDURE usp_ExecuteTransfer
(
@ProductID int,
@FromLocationID smallint,
@ToLocationID smallint,
@QuantityToTransfer smallint
)
AS EXTERNAL NAME [Transaction].[InventoryMover].ExecuteTransfer;
GO
Si tratta dello script di installazione Transact-SQL (InstallDB.sql), che crea il database di controllo nella seconda istanza di SQL Server.
SET NOCOUNT OFF;
GO
PRINT CONVERT(varchar(1000), @@VERSION);
GO
PRINT '';
PRINT 'Started - ' + CONVERT(varchar, GETDATE(), 121);
GO
USE [master];
GO
-- ****************************************
-- Drop Database
-- ****************************************
PRINT '';
PRINT '*** Dropping Database';
GO
IF EXISTS (SELECT [name] FROM [master].[sys].[databases] WHERE [name] = N'InventoryAudit')
DROP DATABASE [InventoryAudit];
-- If the database has any other open connections close the network connection.
IF @@ERROR = 3702
RAISERROR('[InventoryAudit] database cannot be dropped because there are still other open connections', 127, 127) WITH NOWAIT, LOG;
GO
-- ****************************************
-- Create Database
-- ****************************************
PRINT '';
PRINT '*** Creating Database';
GO
DECLARE
@sql_path nvarchar(256),
@sql_cmd nvarchar(256);
SELECT @sql_path = SUBSTRING([physical_name], 1, CHARINDEX(N'master.mdf', LOWER([physical_name])) - 1)
FROM [master].[sys].[master_files]
WHERE [database_id] = 1
AND [file_id] = 1;
-- COLLATE Latin1_General_CS_AS
EXECUTE (N'CREATE DATABASE [InventoryAudit]
ON (NAME = ''InventoryAudit_Data'', FILENAME = N''' + @sql_path + N'InventoryAudit_Data.mdf'', SIZE = 120, FILEGROWTH = 8)
LOG ON (NAME = ''InventoryAudit_Log'', FILENAME = N''' + @sql_path + N'InventoryAudit_Log.ldf'' , SIZE = 2, FILEGROWTH = 96);');
GO
ALTER DATABASE [InventoryAudit]
SET RECOVERY SIMPLE,
ANSI_NULLS ON,
ANSI_PADDING ON,
ANSI_WARNINGS ON,
ARITHABORT ON,
CONCAT_NULL_YIELDS_NULL ON,
QUOTED_IDENTIFIER ON,
NUMERIC_ROUNDABORT OFF,
PAGE_VERIFY CHECKSUM,
ALLOW_SNAPSHOT_ISOLATION OFF;
GO
USE [InventoryAudit];
GO
PRINT '';
PRINT '*** Creating Table';
GO
CREATE TABLE [InventoryChange] (
[InventoryChangeID] int IDENTITY (1, 1) NOT NULL,
[ProductID] int NOT NULL,
[FromLocationID] smallint,
[ToLocationID] smallint,
[Quantity] smallint NOT NULL
);
GO
Di seguito è illustrato lo script test.sqlche consente di testare l'esempio eseguendo le funzioni.
USE AdventureWorks
GO
SELECT 'Before first transfer quantity of adjustable races at Tool Crib = ', Quantity FROM Production.ProductInventory
WHERE ProductID = 1 AND LocationID = 1
SELECT 'Before first transfer quantity of adjustable races at Miscellaneous Storage = ', Quantity FROM Production.ProductInventory
WHERE ProductID = 1 AND LocationID = 6
--Move 12 adjustable race parts (product id 1) from the Tool Crib (location id 1)
--to Miscellaneous Storage (location id 6).
EXEC usp_ExecuteTransfer 1, 1, 6, 12
SELECT 'After first transfer quantity of adjustable races at Tool Crib = ', Quantity FROM Production.ProductInventory
WHERE ProductID = 1 AND LocationID = 1
SELECT 'After first transfer quantity of adjustable races at Miscellaneous Storage = ', Quantity FROM Production.ProductInventory
WHERE ProductID = 1 AND LocationID = 6
--Move them back
EXEC usp_ExecuteTransfer 1, 6, 1, 12
SELECT 'After second transfer quantity of adjustable races at Tool Crib = ', Quantity FROM Production.ProductInventory
WHERE ProductID = 1 AND LocationID = 1
SELECT 'After second transfer quantity of adjustable races at Miscellaneous Storage = ', Quantity FROM Production.ProductInventory
WHERE ProductID = 1 AND LocationID = 6
The following tsql removes the assembly and stored procedure from the database (Cleanup.sql).
USE AdventureWorks
GO
-- Drop existing sproc and assembly if any.
IF EXISTS (SELECT * FROM sys.procedures WHERE [name] = 'usp_ExecuteTransfer')
DROP PROCEDURE usp_ExecuteTransfer;
GO
IF EXISTS (SELECT * FROM sys.assemblies WHERE [name] = 'Transaction')
DROP ASSEMBLY [Transaction];
GO
USE master
GO
IF EXISTS (SELECT * FROM sys.server_principals WHERE [name] = 'ExternalSample_Login')
DROP LOGIN ExternalSample_Login;
GO
IF EXISTS (SELECT * FROM sys.asymmetric_keys WHERE [name] = 'ExternalSample_Key')
DROP ASYMMETRIC KEY ExternalSample_Key;
GO
USE AdventureWorks
GO
Di seguito Transact-SQL viene rimosso il database di controllo dalla seconda istanza
SET NOCOUNT OFF;
GO
PRINT CONVERT(varchar(1000), @@VERSION);
GO
PRINT '';
PRINT 'Started - ' + CONVERT(varchar, GETDATE(), 121);
GO
USE [master];
GO
-- ****************************************
-- Drop Database
-- ****************************************
PRINT '';
PRINT '*** Dropping Database';
GO
IF EXISTS (SELECT [name] FROM [master].[sys].[databases] WHERE [name] = N'InventoryAudit')
DROP DATABASE [InventoryAudit];
-- If the database has any other open connections close the network connection.
IF @@ERROR = 3702
RAISERROR('[InventoryAudit] database cannot be dropped because there are still other open connections', 127, 127) WITH NOWAIT, LOG;
GO
Di seguito Transact-SQL viene rimosso l'assembly e le funzioni dal database.
SE AdventureWorks
GO
-- Drop existing sproc and assembly if any.
IF EXISTS (SELECT * FROM sys.procedures WHERE [name] = 'usp_ExecuteTransfer')
DROP PROCEDURE usp_ExecuteTransfer;
GO
IF EXISTS (SELECT * FROM sys.assemblies WHERE [name] = 'Transaction')
DROP ASSEMBLY [Transaction];
GO
USE master
GO
IF EXISTS (SELECT * FROM sys.server_principals WHERE [name] = 'ExternalSample_Login')
DROP LOGIN ExternalSample_Login;
GO
IF EXISTS (SELECT * FROM sys.asymmetric_keys WHERE [name] = 'ExternalSample_Key')
DROP ASYMMETRIC KEY ExternalSample_Key;
GO
USE AdventureWorks
GO
Vedere anche
Scenari di utilizzo ed esempi per l'integrazione con CLR (Common Language Runtime)