Hi All,

I have a newbie question.

I have an Order class, which contains a set of OrderItems. I am persisting the OrderItems as a set of composite-elements, stored in a table called ORDER_ITEM. Each OrderItem has a relationship to an Item object. Can I nest within each orderItem a unique many-to-one relationship with an Item entity? In order words, I want to persist the Order and related OrderItems without saving any Items.

The mappings are as follows:

Order.hbm.xml:
<class name="poc.domain.Order" schema="HIBERNATE" table="ORDER">

<id name="id" type="long" column="ID">
<generator class="native"/>
</id>

<property name="orderDate" type="date" column="ORDER_DATE" />
<property name="total" type="double" column="TOTAL" />

<set name="orderItems" schema="HIBERNATE" table="ORDER_ITEM">
<key column="ORDER_ID" />
<composite-element class="poc.domain.OrderItem">
<property name="count" type="integer" column="ITEM_COUNT" />
<many-to-one name="item" class="poc.domain.Item" column="ITEM_ID"
unique="true" update="false" insert="false" />
</composite-element>
</set>

</class>

Item.hbm.xml:
<class name="poc.domain.Item" schema="HIBERNATE" table="ITEM">

<id name="id" type="long" column="ID">
<generator class="native"/>
</id>

<property name="name" type="string" column="NAME" />
<property name="description" type="string" column="DESCRIPTION" />
<property name="price" type="double" column="PRICE" />

</class>

I am getting the following error, which I guess means I can't do the nesting but I wanted to make sure:

[object references an unsaved transient instance - save the transient instance before flushing: poc.domain.Item]: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: poc.domain.Item


Thanks!
Steve

Steve,

When you saving Order, the set contains at least one Item that hasn't been saved. You must save all the Item's in your Order before you can save order.

The other option would be to update your hbm.xml configuration to save items in the set.

Hi live216,

Thanks, I think I now know what the problem is, I just don't know how to solve it. The Item objects already exist in a table in the database. I just want to 'attach' references to them to an Order via the Order_Item table. I think I need to pre-load the items into the Hibernate session so their Ids are available but I'm not sure how to do this.

Thanks,
Steve

Ok, figured it out...forgot to load in the Item objects before trying to use them -- Doh!

Sometimes the simplest of errors are the toughest to find and fix.

Glad you fixed it!

Thanks! I guess I was working with 'transient' objects rather than 'persistent' ones.