Hello community members. I'm new to Hibernate, and I want to know if it's applicable to my needs.

For example, I have two tables:

(1) Person (person_id, name, containing age, height, weight)
1, John, 19 yrs, 5'6", 124 lbs
2, Jim, 18yrs, 5'3", 105 lbs
3 Josh, 19 yrs, 5'7", 130 lbs
4 Jon, 19 yrs, 5'8", 124 lbs

(2) Relationships (person_id1 and person_id2, and the name of their relationship)
1, 2, Friend
3, 4, Uncle
2, 4, Cousin
1, 3, Classmate

Here are my questions:
1. Based on some documents that I have read, I am aware of the database mapping from classes to DB through XML... Is it like saying, if I change the schema of the database like creating another table called Age, and transferring the age field from the Person table to that table... I only have to change the XML Mappings?

2. Is it possible in Hibernate to specify some properties... For example, I have these properties and their definitions (ignore the real-world sense):
a. Young - age < 25
b. Healthy - weight < 200 && height < 5" || weight > 100 && age > 20
c. Friendly - age > 20 && the number of relationship must be greater than 2

Can I store these things... and reuse them later? Can I have them stored in XML?

3. Can I do something like this, given this request in English:
Select all healthy and friendly people

How can I represent it in HQL or using Hibernate... reusing the properties I defined in #2 (if it's possible)

Thank you very much.