Entity Framework optimistic concurrency exceptions occur when multi SaveChanges

Question

I using Entity Framework 6. After calling SaveChanges method twice in my code, after DeleteObject, a ConcurrencyException occurred:

entities.DeleteObject(pu);

// First time           
entities.Context.SaveChanges(SaveOptions.None);

// everything is ok

// Second Time     
entities.Context.SaveChanges(SaveOptions.None);

// Concurrency exception

But with using AddObject this exception did not occur !

Exception message is:

Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Handling optimistic concurrency exceptions.

How I can control multiple SaveChanges calls before AcceptAllChanges without a concurrency exception?

Akos Nagy · Accepted Answer · 2017-06-03 18:28:33Z

2

Are you calling the AcceptAllChanges() method before the second save? My understanding is that if you use SaveOptions.None, the context keeps the changes so they can be resubmitted to the database. If the first SaveChanges() succeeds, than the rowversion is updated in the db, but in the context, everything is kept as it was, so the second time it causes the conflict on the rowversion.

answered Jun 3, 2017 at 18:28

Akos Nagy

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Naderi Over a year ago

doesn't exist rowversion or timestamp column in table pu only exist datetime2 , money , int

hasan · Accepted Answer · 2017-06-03 08:09:44Z

0

You can use transaction

var yourContext = ((IObjectContextAdapter)db).ObjectContext;

try {
    yourContext.Connection.Open();
    using (var transaction = new TransactionScope()) {
        
        //you can implement entities.DeleteObject(pu) here

        db.SaveChanges();

        // Do something else

        db.SaveChanges();

        transaction.Complete();
    }
} finally {
    yourContext.Connection.Close();
}

answered Jun 3, 2017 at 8:09

hasan

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1 Comment

Naderi Over a year ago

TransactionScope is for revert , but my question is why every things is OK in first call but i get error for second call and don't have any code between savechanges

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