How do you support optimistic / pessimistic concurrency using NHibernate?
+2
A:
NHibernate, by default, supports optimistic concurrency. Pessimistic concurrency, on the other hand, can be accomplished through the ISession.Lock() method.
These issues are discussed in detail in Chapter 10: Transactions and Concurrency of the Hibernate Docs.
Jon Limjap
2008-09-23 01:03:59
Thanks Jon for the quick reply :-)
Kevin Pang
2008-09-23 01:05:05
Transactions and Concurrency docs now here: http://nhforge.org/doc/nh/en/index.html#transactions
Mauricio Scheffer
2010-08-10 15:34:44
+13
A:
NHibernate supports 2 types of optimistic concurrency.
You can either have it check dirty fields by using "optimistic-lock=dirty" attribute on the "class" element in your mapping files or you can use "optimistic-lock=version" (which is also the default). If you are using version you need to provide a "version" element in your mapping file that maps to a field in your database.
Version can be of type Int64, Int32, Int16, Ticks, Timestamp, or TimeSpan and are automatically incremented on save. See Chapter 5 in the NHibernate documentation for more info.
Ryan Rinaldi
2008-09-23 01:08:19
Chapter 5 of the docs now here: http://nhforge.org/doc/nh/en/index.html#mapping
Mauricio Scheffer
2010-08-10 15:35:35
+1
A:
You can also 'just' manually compare the version numbers (assuming you've added a Version property to your entity).
Clearly Optimistic is the only sane option. Sometimes of course, we have to deal with crazy scenarios however...
ip
2008-10-15 08:28:54