Proper DB design

Question

I am currently working on a project that contains many different tables that use normalization to effectively minimize duplication and NULL cell values. My question pertains on the proper approach to minimizing the amount of tables being utilized and whether or not the approach I am going is bad and the approach I might go has foreseeable problems.

I quickly drew up an example comparable to what I am doing but far more simplified.

Please help my understand which approach is better, or is there a better one then shown?

Image http://img225.imageshack.us/img225/6972/helpdb.jpg

The link to the larger image, http://img225.imageshack.us/img225/6972/helpdb.jpg

Edit: I would like to thank everyone for the overwhelming great answers / comments. I was able to cut my initial data structure tables by roughly 40%; the answers also helped me refine my current data structure, making it far more expansible. I hope to finish this project within the next 2-3 months. Then you can take a look at what you helped me learn and build! Thank you so much and I look to forward contributing to the community where I can now and more as I grow in my knowledge and experience. Thank you again!

Answer 1

Why even have separate tables for different entity types? You could do it like this:

Entity: id_entity , name, entity_type (ie person,dog,fish,etc)

Illness_resilience: entity_id, illness_id, etc...