Is it possible to creat a readonly connection in nHibernate ?
Read-only : where nHibernate will not flush out any changes to the underlying database implicitly or explicitly.
When closing a nhibernate connection it does automatically flush out the changes to the persistent object.
Setting the flush mode to never is one way - but is reversable (i.e some code can reset the flush mode).
I think you've already found the solution, setting flush mode to never. Yes, it is changeable but even if it wasn't, code could simply create another session that had a different flush mode.
I think the appropriate solution is to suggest read-only with session.FlushMode = FlushMode.Never and enforce it by using a connection to the database that only has SELECT permissions (or whatever is appropriate for your situation). Maintaining separate ISessionFactory factories might help by allowing something like ReadOnlySessionFactory.Create().
Take a look at Read Only entities that became available in NHibernate 3.1 GA https://nhibernate.jira.com/browse/NH-908
There is a newer readonly feature in NHibernate (I don't know which version, but it's in 3.3.0 for sure). You can set the session to read only using this:
session.DefaultReadOnly = true
It disables the cache for old values and therefore improves performance and memory consumption.
There is a chapter about read-only entities in the NHibernate reference documentation.
Accumulating updates, and just never flushing seems like a bad solution to me. I posted a similar question. The solution provided uses a different approach. All the events are set to empty, and thus ignored. My feeling is that it's a better approach.
I am surprised that this is not easier to do. I like the entity framework approach of using an extension method .AsNoTracking() which ensures that read only queries remain that way.
