Hi there,

i was searching the Forum on this topic, but didnt find anything relating. Maybe there is already an thread and u just can post the link? :-)

In my domainmodel i´ve got an unidirectional 1:many composit association between Order and OrderDetails. E.g. Order is implementing an ArrayList of OrderDetails. How do i map this best? Should I use an unidirectional Parent/Child-Associaton cause component is not working for Colections?

in Order.hbm.xml something like:

<class name="NHTest.Order", NHTest....>
...
<set name="Details">
<key column="DetailsId"/>
<one-to-many class="NHTest.OrderDetails, NHTest/>
</set>
...
...
</class>

In the documentation is just the bidirectional case explained. Thx for any tips on this, i know i am an beginner :-)

Chris

That sounds pretty straight forward. If you want a one way one-to-many relationship between 2 different objects (such as an order and order details) the most common approach is using the <many-to-many> tag with unique="true", inside a collection tag. For the collection you can use most collection types including maps, lists or sets. You use a <many-to-many> because this creates a seperate joining table between the two seperate class tables. The <one-to-many> tag only defines a link that uses foreign keys, which is an uncommon approach but possible.




The general idea is summarised at the unidirectional one-to-many entry at:
http://www.hibernate.org/hib_docs/v3/re ... l-join-12m


There is one example of a similar case to yours in the hibernate docs at:
http://www.hibernate.org/hib_docs/v3/re ... derproduct

happy hibernating

Michael

Thx that link and example helps a lot!
Chris