I am trying to understand the behavior of associations when second level cache is enabled for an entity. I looked into documentation and it mostly talks about caching simple entities and I couldn't find an answer for my question.

Our application uses lot of associations as you can see in the following simple case:

Basically, my question is when I enable caching (second level) for say, Product_category, will it automatically enable caching for its products association and its many-to-one assocation?

If this is already documented somewhere, would you please direct me?

Thanks!
Madhan.



<hibernate-mapping>
<class name="ProductCategory" table="PRODUCT_CATEGORY" schema="DEALER">
<id name="productCategoryId" type="big_decimal">
<column name="PRODUCT_CATEGORY_ID" precision="22" scale="0" />
<generator class="assigned" />
</id>
<many-to-one name="pageSetup" class="PageSetup" fetch="select" lazy="false">
<column name="PAGE_SETUP_ID" precision="22" scale="0" />
</many-to-one>
<property name="productCategoryName" type="string">
<column name="PRODUCT_CATEGORY_NAME" length="512" not-null="true" />
</property>
<set name="products" inverse="true" lazy="true">
<key>
<column name="PRODUCT_CATEGORY_ID" precision="22" scale="0" />
</key>
<one-to-many class="Product"/>
</set>
</class>
</hibernate-mapping>

===========

I am using hibernate 3.1

You need to configure a separate cache for the association. I've only done this using Spring but as the Spring Javadoc points out - http://static.springframework.org/spring/docs/1.2.x/api/org/springframework/orm/hibernate3/LocalSessionFactoryBean.html#setCollectionCacheStrategies(java.util.Properties) - this is equivalent to the collection-cache element in the Hibernate XML Configuration File (See http://www.hibernate.org/hib_docs/v3/reference/en/html/session-configuration.html#configuration-xmlconfig).

Presumably you can also just specify a <cache> element in the Set configuration, per Section 19.21 in the Hibernate documentation (http://www.hibernate.org/hib_docs/v3/reference/en/html/performance.html#performance-cache) although I haven't tried it.

Hope this helps.

John