Hi all

My name is emerson and I participate of a blog project that uses struts, tiles and hibernate ([url]sf.net/projects/personalblog[/url]). I have a question that didn't manage to answer by myself :)

Currently we have Post and Comment pojos. I'm creating a downloadable pojo that will allow downloads statistics and comments of itens that can be download (it stand for pictures, articles, and whatever).

My question : What's the best way to reuse the same comment pojo and making it related to the downloadable class.

now it is : Post --1----------*--Comment
So that each comment has a link to it's related Post

How to put the downloadable in the action and related to Comments in the same way Post is?

My first solution :




Since there are as lot of production instances, each one has a lot of existing comments that link to existings Posts. If using my proposed solution, should I have a Commentable unique table, or two tables for both Post and Downloadable?? Will hibernate choose the right table depending of the related sub-class??

Sorry if this question is a little dumb, if it is :), some one could sign me to a place where I can find the proper solution??

Emerson Cargnin

Hibernate handles inheritance very well. Personally I like to use joined-subclass because it keeps the database the most orthogonal (if I have subclasses that are very similar, differing by only a field or two than I use subclass but this has limitations).

You can look in the documentation but it's really pretty simple. You have a hierarchy of tables that matches the class hierarchy. Each parent table only has the columns that all the child classes share. Hibernate is very good at correctly executing selects over the correct tables.

It would look something like this: