Difference between Get and Load

The reference provided by Brian explains it quite clearly. However, the main difference is that Load doesn’t hit the database to check and load the entity you require, since it assumes you know the entity exists. The object returned by Load is some kind of proxy that lazily fetches the real data when required or throws an exception if the entity is not found.

Recap:

• Load should be used when you know for sure that an entity with a certain ID exists. The call does not result in a database hit (and thus can be optimized away by NHibernate in certain cases). Beware of the exception that may be raised when the object is accessed if the entity instance doesn’t exist in the DB.

• Get hits the database or session cache to retrieve the entity data. If the entity exists it is returned, otherwise null will be returned. This is the safest way to determine whether an entity with a certain ID exists or not. If you’re not sure what to use, use Get.