How to setup Hibernate cascade correctly

Question

I have following setup

A -> B -> C

A-Mapping:

 <hibernate-mapping>
  <class name="db.base.A" table="A">
      <id name="id" type="java.lang.Integer">
          <column name="id" />        
          <generator class="identity" />    
      </id>
      <set name="Bs" table="BI18n" inverse="true" lazy="true" fetch="select" cascade="all-delete-orphan">
          <key>
              <column name="A_id"  not-null="true" />
          </key>
          <one-to-many class="db.base.B" />
      </set>        
  </class>
</hibernate-mapping>

B:

<hibernate-mapping>
  <class name="db.base.B" table="B">
      <id name="id" type="java.lang.Integer">
          <column name="id" />
          <generator class="identity" />
      </id>
      <many-to-one name="A" class="db.base.A" fetch="select">
          <column name="A_id" not-null="true" />
      </many-to-one>
      <set name="B" table="B" inverse="true" lazy="true" fetch="select" cascade="all-delete-orphan">
          <key>
              <column name="id" not-null="true" />
          </key>
          <one-to-many class="db.base.BI18n" />
      </set>
  </class>
</hibernate-mapping>

SubstanceItentifiedI18n:

<hibernate-mapping>
  <class name="db.base.BI18n" table="B18n">
      <id name="id" type="java.lang.Integer">
          <column name="id" />
          <generator class="identity" />
      </id>
      <many-to-one name="B" class="db.base.B" fetch="select">
          <column name="id" not-null="true" />
      </many-to-one>          
  </class>
</hibernate-mapping>

When I insert a new A with the complete object graph via

HibernateDaoSupport.merge(AObj);

everything is created correctly.

But if I use

HibernateDaoSupport.saveOrUpdate(AObj);

I get a DataIntegrityException

Cannot add or update a child row: a foreign key constraint fails 
(`table`.`B18n`, CONSTRAINT `B18n_fk` 
FOREIGN KEY (`id`) REFERENCES `B` (`id`))

When I look in the log4j log I see that with merge

it inserts B
it inserts B18n

With saveOrUpdate it

inserts B18n, which obviously results in the exception

is this defined (expected) behavior or is there something wrong with my setup.

Are you sure that every association is initialized properly, in both directions (i.e. is seizure has a substanceIdentified, then this substanceIdentified should point to the seizure, and vice-versa)? — JB Nizet, Oct 28 '11 at 21:50
yeah this is actually generated by Jackson. I feed Jackson with JSON data and it generates the whole object graph for me. — Jeremy S., Oct 28 '11 at 21:57

Jeremy S. · Accepted Answer · 2013-03-14T18:40:42.597

1

After some fiddling a found out what the solution was.

I was adding new elements to an existing B. But didn't set the id of the B, because merge does a SELECT of the object graph before it issues a save/update this is no problem.

saveOrUpdate on the other hand doesn't do it. Therefore the exception.

Case closed ;)

edited Mar 14 '13 at 18:40

answered Jan 25 '12 at 17:40

Jeremy S.

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How to setup Hibernate cascade correctly

1 Answers1