we have USERS table:



and SKILLS table:



and we have "mediator" table, between USERS and SKILLS tables -- USERS_SKILLS:




in practice it looks the following way.
there can be many USERS's, each of them has name and id.
also, there are a lot of SKILLS's, each of them as name and id.

each user can set for specified skills how many years he is experienced with it. (record in USERS_SKILLS)
if there is no such record - user has no experience with such skill.

how can we map this correctly?
can you help me with code example's of such mapping?

it would be perfect, if after mapping we will be able to see all SKILLS the following way (i.e. for user with id 1):


getUser(1).getSkills()

and we will have a list of ALL skills (from SKILLS table) and each of them will have information on how many years user is expereinced:

...
(in iteration)

Skill s;
...
s.getYears()
..





Thanks for any help!

The association between User and Skill is many-to-many, but you need to save additional info into the linking table (US_SKILL_YEARS in the USERS_SKILLS). So you cannot use many-to-many association in your mapping. You need additional linking entity class eg UserSkill. Please read the following "Best Practice": Don't use exotic association mappings on the http://www.hibernate.org/hib_docs/reference/en/html/best-practices.html

You asked for an example of the mapping, you could look into the following junit test
http://opensource.atlassian.com/project ... st-src.zip

There is a many-to-many association between MoslemMan and Woman through the Harem linking class. You can use your User instead of my MoslemMan, your Skill instead of my Woman and UserSkill instead of Harem. Everything should work fine.