hb 3.0.4: mant-to-one relation violates db constraint

ciukes · **Joined:** Thu Aug 18, 2005 6:59 pm **Posts:** 2

Hello everyone!

I'm using Hibernate 3.0.4 with PostgreSQL 8.0.1 on Win32.
My problem is with many-to-one relation mapping.

There is such model:

Code:

(many) templates |---------------------------------| template_models(one)

and constraint in DDL (PostgreSQL):

Code:

CREATE TABLE TEMPLATES (
...
CONSTRAINT FK_TEMPLATE_REFERENCE_MODEL 
    FOREIGN KEY (TEMPLATE_MODELS_ID) 
    REFERENCES TEMPLATE_MODELS (TEMPLATE_MODELS_ID)
...
)

I have made such relation definition in TemplateBean's hibernate mapping file (removed not important parts):

Code:

<class name="TemplateBean"
    table="templates"
    lazy="false">
    ...
    <many-to-one name="templateModelBean" 
        class="TemplateModelBean" 
        column="template_models_id"
        cascade="save-update,delete-orphans"
    />
    ...
</class>

TemplateModelBean's mapping doesn't contain any reference mapping to TemplateBean.

This is the problem.... when I do delete like this:

Code:

TemplateBean templateBean=...;
transaction=hibernateSession.beginTransaction();
hibernateSession.delete(templateBean);
transaction.commit();

I always get this exception in line 4:

Code:

java.sql.SQLException: ERROR: update or delete on "template_models" violates foreign key constraint "fk_template_reference_model" on "templates"
   at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:1471)
   at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1256)
   at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:334)
   at org.postgresql.jdbc2.AbstractJdbc2Statement.executeBatch(AbstractJdbc2Statement.java:2451)
   at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeBatch(NewProxyPreparedStatement.java:1722)
   at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:57)
   at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:174)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:226)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:141)
   at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:274)
   at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
   at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:730)
   at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:324)
   at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:86)

Workaround is to remove constraint in DDL - but this is not the solution I want. Problem is that Hibernate removes object graph in wrong order.
Am I missing some hibernate-mapping-magic ?
How to guide Hibernate to delete TemplateBean before TemplateModelBean?
Does anyone had similar problem?

Basilio · **Posted:** Thu Aug 18, 2005 7:42 pm

Remove delete-orphans cascade option or use bidirectional mapping with inverse="true" set. It is not clear what is life cycle of those object and relationships between them to tell more how to better implement that.

ciukes · **Joined:** Thu Aug 18, 2005 6:59 pm **Posts:** 2

Basilio wrote:

Remove delete-orphans cascade option

This is unacceptable. Orphaned entities have to be removed from database.

Basilio wrote:

or use bidirectional mapping with inverse="true" set.

I have made such investigation. Nothing changed.

Basilio wrote:

It is not clear what is life cycle of those object and relationships between them to tell more how to better implement that.

TemplateModelBean is created with first TemplateBean refering to it (db constraint is guarantee).
TemplateModelBean may be reffered with many TemplateBean.
TemplateModelBean may exist as long as any TemplateBean refers to it.
When no TemplateBean refers TemplateModelBean then TemplateModelBean have to be removed (This is why cascade="..., delete-orphan" is used.).