I've had good success with Hibernate and my current model. I have a particular situation which actually occurs in a few places. I think i can figure out a way to "get it to work", but i would appreciate some suggestions of a solution that may make most sense.

Since i have the flexibility to change either the java class structure (somewhat) and/or the database, I'll try to explain it conceptually, then use an example.

Party object contains information about the Party. Name, SS#, etc. It's actually an abstract class with Business and Individual as derived classes.

Party can contain any number of Address objects of a certain address type. That is the key difference. An addressType can be mailing, residential, legal, etc. These addressTypes are stored internally as integers. There may only be one address of any one addressType attached to a Party. However the same address can be attached to a Party for any number of types. That is, the same address can be all known address Types.


Currently the methods in Party to handle this are:

void setAddress(Address address, int addressType)
Address getAddress(int addressType)

Party backs these methods with logic to insure only one addressType, and a Map.

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Current status.

DB perspective.
Party table contains PartyID, Address Table contains AddressID
PartyAddress Table contains partyID,addressType,addressID with partyID,role as primary key (can will adjust if necessary)

Java

Assuming that i'd need a class for PartyAddress, I have an inner class Party$PartyAddress that contains addressType and Address object. I've sinced added a reference to the Party that owns it. (don't know if i need to, hoped i didn't).

Party contains a Map of all PartyAddress objects keyed by addressType.

Mapping File.
So, i'm figuring i would define a separate peristable class Party$PartyAddress. And have a collection of these guys inside Party. As i was creating the map for Party$PartyAddress, i then needed the primary key, then realized it needed to be composite, then realised the composite key was made up of the partyID inside the Party object in this class along with the addressType.
Wasn't sure how to handle that so was toying with adding a primary identity column to PartyAddress instead, and using that as primary key ...

which got me to wondering if i was even any where on the right track.

So, for any of you more experienced Hibernate users, i'm looking for suggestions. Maybe there is an easy pattern to use with Hibernate that i've just missed.

Note, i have a similar pattern/problem in other parts of the object model. A Vehicle object contains many Partys/Occupants of a certain type (owner, registrant etc).

so, this solution will be replicated elsewhere.

Please, any suggestions on how to handle this will be MUCH appreciated.

I think a <composite-element> for your association is just what you need. Take a look at the second example at http://www.hibernate.org/hib_docs/reference/html/components.html#components-s2-2. And yes, don't use inner classes, they will not work very nice (non-static inner classes can't be mapped at all).

Thanks for the help! I was looking at that scenario. Wasn't able to get it quite working and then i found that since my only extra attribute in the class was the key to the map, i went back to the simple. I guess i overcomplicated my requirement.



using many to many and it worked flawlessly. Thanks for the help. In my day or 2 of finding and trying this product out, i am extremely impressed.

This will definately solve our problems. I will now turn my attention to designing a DAO abstraction for our model suitable for our application.

Looking forward to working with it.