Question

The manual says that you can create a record as such:

using (Session.Open(domain))
{
    using (var transactionScope = Transaction.Open())
    {
  // Creating new persistent object
  var helloWorld = new MyEntity
  {
      Text = "Hello World!"
  };

        // Committing transaction
  transactionScope .Complete();
    }
}

However when I do this I get the following exception:

Active Session is required for this operation. Use Session.Open(...) to open it.

The sample code implements a constructor that takes session which does work:

public MyEntity(Session session) : base(session) {}

Has this changed in the 4.4 beta since the manual was written? What am I doing wrong? Do I have to implement this constructor in all my classes?

Accepted Answer

4

As far as I have grasped this, you either have to implement such a constructor for entities that passes the session object to the base constructor or you have to utilize automatic session activation - like this:

DomainConfiguration domainConfiguration = DomainConfiguration.Load(...);
domainConfiguration.Types.Register(typeof(...).Assembly, typeof(...).Namespace);
SessionConfiguration sessionConfiguration = new SessionConfiguration(SessionOptions.AutoActivation);
domainConfiguration.Sessions.Add(sessionConfiguration);
Domain domain = Domain.Build(domainConfiguration);
using (var session = domain.OpenSession(sessionConfiguration))
using (var transactionScope = session.OpenTransaction())
{
    // create Entities
    transactionScope.Complete();
}

answered Dec 22 '10 at 17:43

Sebastian Hauer
87●1●1●3

Thanks, Sebastian, you are absolutely right.

The only thing I could add is that it might be more convenient to make use of Session Profiles (Client, Server & Legacy ones). A Session Profile notion represents a set of predefined Session Options and is introduced in 4.4 Beta 1. More information on the subject can be found in Release Notes.

(Dec 22 '10 at 23:19) Dmitri Maximov

I am using 4.4 Beta 1 and I hadn't read the release notes. Thanks for answering the question so quickly. Just a few more questions:

Is the new session profile without automatic session creation included to ensure thread safety?
Would be have problems if we use the legacy mode with multiple threads?
If we use the new session profile do we have to create constructors that take a session as a parameter in all of our entities?

(Dec 23 '10 at 16:53) slamb2k

1

Session is not thread-safe in any way
You won't have any problems. The only thing you should care about is session activation and deactivation within a thread
There are 2 options: you create constructors that take a session instance as a parameter or you use the following pattern with temporary Session activation and construct your entities inside this region, e.g.:

using (session.Activate()) {

// Here we can use parameterless constrictor

var person = new Person();

}

Hope that helps.

(Dec 24 '10 at 05:47) Dmitri Maximov

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