How to Write a Transaction to Cover Moving a File and Inserting Record in Database

How to write a transaction to cover Moving a file and Inserting record in database?

Try to use .NET Transactional File Manager

This library allows you to wrap file system operations in transactions like this:

// Wrap a file copy and a database insert in the same transaction
TxFileManager fileMgr = new TxFileManager();
using (TransactionScope scope1 = new TransactionScope())
{
    // Copy a file
    fileMgr.Copy(srcFileName, destFileName);

    // Insert a database record
    dbMgr.ExecuteNonQuery(insertSql);

    scope1.Complete();
} 

Atomic transaction for both file system and DB operations

Yes Linq to Sql supports .Net Transactions.SaveChanges applies Transaction with Isolation level ReadCommitted. If you do have to apply More than one SaveChanges within one Transaction then you explicitly apply Transactions. EF SaveChanges first checks whether there is already transaction it continues with it if not then It applies its own Transaction.If there is only one SaveChanges per transaction then there is no need to apply Transaction .

Atomicity: Implementing a Resource Manager

First, i think you should make your resource manager durable:

https://learn.microsoft.com/en-us/dotnet/api/system.transactions.transaction.enlistdurable?redirectedfrom=MSDN&view=net-5.0#overloads

Then you can save your file moving operation to a durable storage (file, database table,..) in the Prepare method (phase 1 of 2-phase commit protocol) with some format like (Operation:FileMove, SrcFile, DesFile), this also helps with recovery later if the process crashes:

https://learn.microsoft.com/en-us/dotnet/api/system.transactions.preparingenlistment?view=net-5.0 .

public void Prepare(PreparingEnlistment preparingEnlistment)
    {
        Console.WriteLine("Prepare notification received");

        //Validate if the File.Move is valid if it's executed later, then save your file moving operation to a temporary durable storage

        //If work finished correctly, reply prepared
        preparingEnlistment.Prepared();

        // otherwise, do a ForceRollback
        preparingEnlistment.ForceRollback();
    }

In phase 2 (Commit), you can load the operation from the durable storage to actually move the file (use retry to ensure true atomic operation)

 public void Commit(Enlistment enlistment)
    {
        Console.WriteLine("Commit notification received");

        //Read to file moving operation from phase 1 to move the file and retry if the failure is transient

        //Declare done on the enlistment when the files have been moved 
        enlistment.Done();
    }

The point of saving the file moving operation in phase 1 is to ensure that:

• If any failure occurs in the Commit phase (due to File.Move operation accross file system boundaries) => enlistment.Done() is not called so the Commit method can be executed later, we still have the information in phase 1 to retry.
• Because our resource manager is durable, if the process crashes while in Commit method, in the recovery process we can retry the file moving operation thanks to the information persisted in Prepare phase

How can I use Transaction in FILE OPERATIONS?

I think you can only do this manually. Look at UnitOfWork from Martin Fowler, you can realize something like he described

Also check this links maybe the help you

• transactional-file-manager
• STM.NET
• Article from MSDN

How to transaction a IO operation and a database execution?

You can use Transactional NTFS (TxF). This provides the ability to perform actions that are fully atomic, consistent, isolated, and durable for file operations.

It can be intergrated to work with a large number of other transactional technologies. Because TxF uses the new Kernel Transaction Manager (KTM) features, and because the new KTM can work directly with the Microsoft® Distributed Transaction Coordinator (DTC).

Any technology that can work with DTC as a transaction coordinator can use transacted file operations within a single transaction. This means that you can now enlist transacted file operations within the same transaction as SQL operations, Web service calls via WS-AtomicTransaction, Windows Communication Foundation services via the OleTransactionProtocol, or even transacted MSMQ operations.

An example of file and database atomic transaction:

using (connectionDb)
{
    connectionDb.Open();
    using (var ts = new System.Transactions.TransactionScope())
    {
        try
        {
            File.Copy(sourceFileName, destFileName, overwrite);
            connectionDb.ExecuteNonQuery();
            ts.Complete();
        }
        catch (Exception)
        {
            throw;
        }
        finally
        { }
    }
}

See the following links for more information:

TxF on Codeplex

Msdn reference

Note: Remember DTC comes with a heavy performance penalty.

File System Transactions using .NET on WinXP

You could create your own class that implements IEnlistmentNotification.

Here's an example of someone that did: http://www.chinhdo.com/20080825/transactional-file-manager/

TransactionScope With Files In C#

You're looking for Transactional NTFS, introduced by Windows Vista.

Here is a managed wrapper.

So TransactionScope is only used when dealing with database

From docs:

The System.Transactions infrastructure makes transactional
programming simple and efficient throughout the platform by supporting
transactions initiated in SQL Server, ADO.NET, MSMQ, and the
Microsoft Distributed Transaction Coordinator (MSDTC).

So, you can't use System.Transactions with the file system.

There is Transactional NTFS component but Microsoft strongly recommends developers utilize alternative means to achieve your applications needs.

Also you can look at TransactionalFileMgr

Or as said @ken2k, you need to implement IEnlistmentNotification and allow manual standard file operations to work with TransactionScope. For instance, to enable rollback for a write operation on an existing file, it first creates a backup of the file that will be written, then writes to the backuped file, and finally replaces the initial file with the backuped/modified file if the transaction is committed, or deletes the backup file if the transaction is rollbacked

PHP File Upload - Ensure both file is uploaded AND database updated

I would use this order:

First method: operation order dependent

• Form validation
• Check if file was uploaded (don't move it from temp, yet)
• Generate new filename based on your free choice
• Insert data about the file to database using newly generated filename
• Only then, if there's not exception thrown, move the file from temp using filename above. Otherwise, file will be deleted automatically on request end
• If file moving failed for some reason you should remove record from database.

I strongly suggest using some PDO-like library to "talk" to database as these throw exceptions, instead of raising errors (like mysql_** function). That way you will know for sure if your query succeeded without constantly checking result of database functions...

Second method: Transactions

• Form validation
• Check if file was uploaded (don't move it from temp, yet)
• Generate new filename based on your free choice
• Start transaction
• "Insert" data about the file to database using newly generated filename.
• Move the file from temp using filename above. If for some reason file move fails, throw an execption.
• Commit transaction
• At this point you're sure that both file is moved and data persisted properly.

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