#StackBounty: #c# #database #entity-framework-core #locking Is optimistic locking enough to secure operations such as funds transfer?

Bounty: 50

In the following example we may run into a concurrency error where if the sender decides to send funds to 2 different receivers in the same time then both receivers may get the money while the sender will only be charged once.

public async Task SendMoney(int amount, int sender, int receiver)
    await using var dbContext = new ApplicationDbContext();
    var person1 = await dbContext.Persons.FirstOrDefaultAsync(p => p.Id == sender);
    var person2 = await dbContext.Persons.FirstOrDefaultAsync(p => p.Id == receiver);
    if (person1.Balance >= amount)
        person1.Balance -= amount;
        person2.Balance += amount;
    await dbContext.SaveChangesAsync();

What would be the best way to avoid such scenario and make this operation secure?

Is introducing optimistic locking by adding timestamp property [Timestamp] public byte[] Version { get; set; } to the Person model enough to make sure there is no way of duplicating funds?

I mostly care about the security of avoiding duplication. Properly handling exceptions such as DbUpdateConcurrencyException in order to provide smooth user experience is not part of my question.

Get this bounty!!!

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