How do I map the following association in Hibernate (v3.x)?

Well, you can use either annotations or an XML mapping file. Any exceptions you get?

I was actually wondering how to write the specific XML to map this in hibernate.cfg.xml since it is a complex association/relationship.

I currently have (Hibernate) JavaBeans for the following tables and have been able to set them up (e.g. Part.hbm.xml) and do CRUD operation on each table individually using Hibernate:
1. Part
2. Manufacturer
3. Category

However, now I need to put together RecommendedParts.

To further elaborate, I'm wondering if:

1. Part is the Entity with the "primary key"?

2. RecommendedParts is a collection tied to Part using a foreign key (collections column key)? Do I use <bag> here?

3. Manufacturer and Category are values (<set>)?

if you give the association a surrogate id, you can map it with something like:



If you prefer to use as the PK of the association the key composed with the FK of the other three tables, you can use a <composite_id>.

Thank you. I had a couple of questions:

1. If I want to use a List instead of a Set (easier to bind it to Spring MVC), should I simply use <bag> instead of <set>?

2. If I'm using "assigned" generators, does that cause a problem?

3. At this point, I'm mainly concerned with using the "RecommendedParts" class for it's corresponding screen (using Spring MVC).

Thanks again.


<hibernate-mapping>
<class name="Part" table="part">
<id name="id" column="id">
<generator class="assigned"\>
</id>
<set name="RecommendParts" cascade="all" inverse="true">
<key column="part_id"/>
<one-to-many class="RecommendPart"/>
</set>
</class>

<class name="Manufacturer" table="manufacturer">
<id name="id" column="id">
<generator class="assigned"\>
</id>
<set name="RecommendParts" cascade="all" inverse="true">
<key column="manufacturer_id"/>
<one-to-many class="RecommendPart"/>
</set>
</class>

<class name="Category" table="category">
<id name="id" column="id">
<generator class="assigned"\>
</id>
<set name="RecommendParts" cascade="all" inverse="true">
<key column="category_id"/>
<one-to-many class="RecommendPart"/>
</set>
</class>

<class name="RecommendPart" table="RecommendParts">
<id name="id" column="id">
<generator class="sequence"\>
</id>
<many-to-one name="manufacturer" class="Manufacturer" column="manufacturer_id"/>
<many-to-one name="part" class="Part" column="part_id"/>
<many-to-one name="category" class="Category" column="category_id"/>
</class>
</hibernate-mapping> [/quote]

1. If you don't need to retain the order of the List, you can map it to a <bag>. If you need to retain the order, map it to a <list>. Remember that if you use a <list> mapping, you need to map de index of the list using the <list-index> property.

2. No problem. I used sequence as a generic example.

3. I have never used Spring MVC, so I cannot advice you here.