Hi All,

I have must what be a common problem and I found some indication of how togo about this in the Tips & Tricks but it didn't make sense to me...

so example tables :

Title (id,name)
Contributor (id,name)
TitleContributor (id,titleid,contributorid,role)
Role(id,name)

I'm sure that you understand the relationship above and that TitleContributor is the intersection table between Title & Contributor and that each relationship can be assigned to a role (Author,Illustrator,Editor etc)

When I load the Title object then I can easily get all assigned Contributor objects by making a mapping one-to-many relationship

but using this method I dont get my Role object, which is in a one to one relationship with TitleContributor...

Anyone knows the best way to go about this ?


Kind Regards,

Lennart

It looks like you want something like:

class Title {
private List<TitleContributor> contributors; ...
}
class Contributor...
class Role....
class TitleContributor {
private Contibutor contrib;
private Role role;
}

Title mapping includes:
<idbag name="contributors" table="TitleContributor">
<collection-id column="id" type="long">
<generator class="sequence"/>
</collection-id>

<key column="titleid">
<composite-element class="TitleContributor">
<many-to-one name="role" class="Role" column="role"/>
<many-to-one name="contrib" class="Contributor" column="contributorid"/>
</composite-element>
</idbag>

The TitleContributor class, being a composite element, doesn't get its own mapping file.

By the way, do you really need the id in the TitleContributor table? Couldn't you have a composite key of titleid,role and contributor? If so, you could change the List<TitleContributor> in Title into a Set, change the idbag in the mapping to a set, and remove the collection-id.