ここに良い例があります
http://msdn.microsoft.com/en-us/library/system.transactions.transactionscope(v=vs.90).aspx#Y500
この例(上記のリンク、以下のコード)では、SQL接続オブジェクトがトランザクションに自動的に参加します。したがって、これらのSQLコマンドは、トランザクションが完了する前にコミットされません(scope.Complete
)。このようにして、両方が2つの別々のサーバーで発生するのは、もう一方が発生した場合のみです。例外があると、両方がロールバックされます。
ネストされたスコープを説明するのはそのページのコンテキストのみであるため、例は明確ではありません。この例は、何か有用なことをするコードではなく、ネストされていると見なされるものを示しています。
これは私が非常に明確だと思うマイクロソフトのサンプルコードです:
// This function takes arguments for 2 connection strings and commands to create a transaction
// involving two SQL Servers. It returns a value > 0 if the transaction is committed, 0 if the
// transaction is rolled back. To test this code, you can connect to two different databases
// on the same server by altering the connection string, or to another 3rd party RDBMS by
// altering the code in the connection2 code block.
static public int CreateTransactionScope(
string connectString1, string connectString2,
string commandText1, string commandText2)
{
// Initialize the return value to zero and create a StringWriter to display results.
int returnValue = 0;
System.IO.StringWriter writer = new System.IO.StringWriter();
try
{
// Create the TransactionScope to execute the commands, guaranteeing
// that both commands can commit or roll back as a single unit of work.
using (TransactionScope scope = new TransactionScope())
{
using (SqlConnection connection1 = new SqlConnection(connectString1))
{
// Opening the connection automatically enlists it in the
// TransactionScope as a lightweight transaction.
connection1.Open();
// Create the SqlCommand object and execute the first command.
SqlCommand command1 = new SqlCommand(commandText1, connection1);
returnValue = command1.ExecuteNonQuery();
writer.WriteLine("Rows to be affected by command1: {0}", returnValue);
// If you get here, this means that command1 succeeded. By nesting
// the using block for connection2 inside that of connection1, you
// conserve server and network resources as connection2 is opened
// only when there is a chance that the transaction can commit.
using (SqlConnection connection2 = new SqlConnection(connectString2))
{
// The transaction is escalated to a full distributed
// transaction when connection2 is opened.
connection2.Open();
// Execute the second command in the second database.
returnValue = 0;
SqlCommand command2 = new SqlCommand(commandText2, connection2);
returnValue = command2.ExecuteNonQuery();
writer.WriteLine("Rows to be affected by command2: {0}", returnValue);
}
}
// The Complete method commits the transaction. If an exception has been thrown,
// Complete is not called and the transaction is rolled back.
scope.Complete();
}
}
catch (TransactionAbortedException ex)
{
writer.WriteLine("TransactionAbortedException Message: {0}", ex.Message);
}
catch (ApplicationException ex)
{
writer.WriteLine("ApplicationException Message: {0}", ex.Message);
}
// Display messages.
Console.WriteLine(writer.ToString());
return returnValue;
}