Hello everybody,

I have a problem mapping part of my database mode and hope that somebody here can help me. I googled quite a bit on this, but I suspect that I use the wrong searchterms (since I have not found an answer yet).

I have the following database model:



In the domainmodel, Series has a map of Attributes. No problem mapping that. Series also has a list of Books and a Book has a reference to its Series. Again, no problems. But now comes the tricky part. I want to be able to ask a Book the question "give me your value of this attribute of your series". So I e.g. want Book to have a Map with 'Attribute' as key and 'value' as value.

I have no idea how to map this. Help... :)

With kind regards,

Martijn Onderwater (The Netherlands)

Have a look at http://www.hibernate.org/hib_docs/v3/re ... ns-ternary to see instructions about how to map a Map.

If you can afford it, the book "Java Persistence with Hibernate" (see above) will also provide you with a comprehensive explanation about this (and lots of other things :)).

Hi Batmat,

This would indeed work. I could introduce an entity SeriesAttribute into my domainmodel, with a reference to a Series and an Attribute in it. The table 'tb_book_attribute_values' would then be a normal many-to-many relation.

But I don't really want to introduce an entity into my domainmodel just in order to get Hibernate to work. Of course, I will do it if it is the only to get my databasemodel mapped with Hibernate. But I'll just look a little further for now.

Does anybody have any more ideas?

/Martijn