NHibernate Pitfalls: Versioned Entities Are Not Batcheable

This is part of a series of posts about NHibernate Pitfalls. See the entire collection here.

This is a problem similar to the one with native id generators. Basically, because there are different versioning strategies – timestamp, counter, native, etc, – NHibernate needs to issue a SELECT after a versioned entity is INSERTEd or UPDATEd. While this wouldn’t be necessary when NHibernate manages the version on the “client side”, like:

   1: UPDATE MyEntity SET Version = 2 WHERE ...;

   2: //or

   3: UPDATE MyEntity SET Version = GETDATE() WHERE ...;

But not if the version is handled on the database side, like when using SQL Server’s ROWVERSION/TIMESTAMP columns or Oracle’s ORA_ROWSCN pseudo-columns. In these cases, NHibernate needs to issue a SELECT after each INSERT or UPDATE:

   1: UPDATE MyEntity SET ... WHERE ...;

   2: SELECT Version FROM MyEntity WHERE ...;

This breaks batching, because it needs to be done immediately after each INSERT/UPDATE.