Hello,

I'd like to get some help on this simple issue, possibly due to my ignorance of SQL.

I have a simple class that contains a set mapped as one-to-many. When I use the left join fetch to hidrate the collection with one select, I get as a result each one class of the 'one' end of the relation per item found on the many.
Maybe I wrongly assumed that I'd get the 'one' class and hibernate would add each of the items found for the 'many' side to the collection.

My mappings follow:

<class name="net.Property" table="property" dynamic-update="true">
<id name="id" column="id" type="long">
<generator class="native"/>
</id>
<property name="name" column="property_name"/>
<property name="type" column="property_type"/>
<property name="rooms" column="number_of_rooms"/>
<property name="bathrooms" column="number_of_bathrooms"/>
<property name="floors" column="number_of_floors"/>
<property name="orientation"/>
<property name="status"/>
<property name="summary"/>
<property name="description"/>
<property name="price"/>
<property name="nativeCurrency" column="native_currency"/>
<property name="currency"/>
<property name="partnerId" column="partner_id"/>
<property name="userId" column="user_id"/>
<property name="visible" type="boolean"/>
<property name="creationDate" column="creation_date"/>
<property name="lastModifiedDate" column="last_modified_date"/>
<property name="offMarketDate" column="off_market_date"/>

<component name="address" class="net.Address">
<property name="street1" column="address"/>
<property name="city"/>
<property name="location"/>
<property name="country"/>
<property name="state" column="state_province"/>
<property name="postcode" column="postcode"/>
</component>

<set name="pictures" cascade="all" lazy="true" inverse="true">
<key column="property_id"/>
<one-to-many class="net.Picture" />
</set>

<set name="auditLog" cascade="delete" lazy="true" inverse="true" order-by="access_date desc">
<key column="property_id"/>
<one-to-many class="net.Audit" />
</set>
</class>



And for the 'many' side:

<class name="net.Picture" table="picture">
<id name="id" column="id" type="long">
<generator class="native"/>
</id>
<property name="propertyId" column="property_id" insert="false" update="false"/>
<property name="pictureName" column="picture_name"/>
<property name="thumbnailName" column="thumbnail_name"/>
<property name="pictureURL" column="picture_url"/>
<property name="thumbnailURL" column="thumbnail_url"/>
<property name="pictureWidth" column="picture_width"/>
<property name="pictureHeight" column="picture_height"/>
<property name="thumbnailWidth" column="thumbnail_width"/>
<property name="thumbnailHeight" column="thumbnail_height"/>
<property name="visible" type="boolean"/>
<many-to-one name="property" column="property_id" cascade="none" not-null="true" />
</class>

Cheers
jorge

This is a known behaviour. http://www.hibernate.org/74.html#A4

Ah, ok. Sorry about that, it seems I overlooked that.

Now could I get an expert opinion on the advantages of that? I save database hits for the extra memory search burden. What should be the threshold, the point of no return? At the moment I'm returning a couple of hundreds of those Property classes. What if it escalates to 1000s? Which approach is more scalable, you reckon?

Cheers
jorge

Thats a very vague question. What you should do is ask your DBA for advice.