Implementing if-not-exists-insert using Entity Framework without race conditions

Question

Using LINQ-to-Entities 4.0, is there a correct pattern or construct for safely implementing \"if not exists then insert\"?

For example, I currently have a table that tra

Answer 1

You could try to wrap it in a transaction combined with the 'famous' try/catch pattern:

using (var scope = new TransactionScope())
try
{
//...do your thing...
scope.Complete();
}
catch (UpdateException ex)
{
// here the second request ends up...
}