Question

I saw in some NHibernate examples that an abstract base entity class is used, which has overridden Equals , GetHashCode , to handle transient entities , proxy object (in lazy loading scenario .. I guess) .

Is it really necessary to implement such an abstract base entity class to derive all my entities ?

Answer 1

Overridding Equals is definetely required if you want to do lazy loading.
This is because NHibernate relies on the Equals method to determine equality. The default is reference equality.

When NHibernate implements lazy loading, it uses proxy objects, which are subclasses of the real entity class, with every member overridden to enable lazy loading.

Hence for your application to recognise that a proxy object is the same as the object it is meant to be the real instance – it shouldn’t be aware of the proxy object at all.

So you must override the Equals operator to intelligently recognise equality (after checking reference equality … etc) that objects are equal if their IDs are equal.