Dealing nested transactions using NHibernate in Sharp Architecture

Question

Hi guys,

I would like to know how to deal with nested transactions e.g. Between one begin and comit, I have another begin and comit. The reason I am asking you is because in my ApplicationServices project I have services that depends on other services. And a method of a parent service begins a transaction and depending upon some logic, it might have to call one of the methods of the dependent child services, that also in turn perform begin and commit. The Child services method are also being used independently as well directy from the controllers, therefore I have to use begin and commit in the child services.

So in short, basically I will end up having somethign like this

   using( Repository1.DbContext.BeginTransaction() )
   {
      try
      {
         .....
         .....
         using( Repository2.DbContext.BeginTransaction() )
         {
            try
            {
               .....
               .....
               Repository2.DbContext.CommitTransaction()
            }
            catch
            {
               Repository2.DbContext.RollBack();
               throw;
            }
        }
        Repository1.DbContext.CommitTransaction()
      }
      catch
      {
         Repository1.DbContext.RollBack();
         throw;
      }
   }

So there are nested begins and commits. I would like to know

-what would be the behaviour, when the nested Repository2 gets committed successfully but the parent Repository1 is rollbacked ?

How can I control this behaviour in code e.g.

-if I don't want to make child transaction part of the parent transaction. -how to figure out wether a transaction is already running before creating a child transaction

or if there is another elegant solution to this problem?

Thanks Nabeel

Answer 1

NHibernate does not support nested transactions. Is the DbContext is the same for both Repository1 and Repository2? If that's the case then they can participate in the same transaction. If not, you'll have to split the transactions into two methods or look at the System.Transactions namespace.

Answer 2

If you place your transaction boundaries at your controllers level then I would say you don't need nested transactions.

Answer 3

Have you tried the UnitOfWork attribute in the Sharp-Architecture-Contrib project?

http://github.com/codai/Sharp-Architecture-Contrib

http://tomcabanski.spaces.live.com/blog/cns!E0D3617496209F45!220.entry

http://wiki.sharparchitecture.net/ContribConfiguration.ashx

http://wiki.sharparchitecture.net/ContribUnitOfWork.ashx