Hey,

Assume you have the following mapping:
AAA - > BBB
6 classes extend from BBB
AAAEtend from AAA (The only BBB implementation that relevant for AAAExtend are BBB1,BBB2)

When you ask for AAAExtend you will get a big query that have 6 left-outer join (in case of join inheritance) and a lot of columns in the select (The columns of BBB3…BBB6 , which are not relevant).

I think on write some extension to hibernate that can restrict the type of the reference and will not generate query with all the columns in the hierarchy.

What do you think?