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Hibernate version: 3.0

Mapping documents:
<class name="Child">
<id name="id" column="childId">
</id>
<many-to-one name="parent" cascade="all"
column="parentId"
not-null="true"/>
/class>
<class name="parent">
<id name="id" column="parentId">
</id>
/class>

Code between sessionFactory.openSession() and session.close():

Session session = TestEntity.currentSession();
//STORE
Transaction tx = session.beginTransaction();
Parent parent = new Parent();
parent.setParentId("101");
session.delete(parent);
tx.commit();
sesson.close();

Full stack trace of any exception that occurs:
Exception in thread "main" org.hibernate.exception.ConstraintViolationException: could not delete: [*****.Parent#101]
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71)
******.....
Caused by: java.sql.SQLException: Cannot delete or update a parent row: a foreign key constraint fails

Name and version of the database you are using:
mysql 4.1.11
The generated SQL (show_sql=true):
dont have them
Debug level Hibernate log excerpt:
dont have them

Problems with Session and transaction handling?
HI,
This is Poonam.
The problem here is when I try to delete the Parent it gives exception of foreign key constraint failed.
My expectation was delete of a Parent should also delete the Child as I have used cascade="all" in Child.
Can some one tell me how to achieve a cascade delete using seprate relations for Parent and Child.
Note: I do not want to use the approach of declaring the child as a collection inside the parent as it becomes a heavy operation when I do getParent() all children and then all successors of each child are retrieved. This becomes an expensive operation.
Can someone please help me using a cascade delete without using collections.
Thanks in advance
-Poonam.




Read this: http://hibernate.org/42.html

In this case you have to define cascade delete at your database level.
"ON DELETE CASCADE "

Thanks in advance Sagi...
but that can be done even without using Hibernate using DDL statements.
My question is how do I define such a relationship in the Hibernate mapping file.
Has nobody come across this problem as of now..or can someone provide me links to applications that have successfully defined such a relationship.
-Poonam.

you need to define one-to-many relation in Parent class also,
here cascade is "delete-orphan" means, delete the child if parent does not exist, lasy is set to true so that it does not become expensive operation.



Regards,

Rohit (Sagi)

Sorry Rohit that does not solve my problem.
I had mentioned in my first post that I am looking at a solution which is without using collections.
Using <set> with lazy='true' makes it as good as not related,
coz the set of children will not be fetched when I fetch a parent.

Also, I had tried to set the max_fetch_depth=1 with lazy=false using collections so that only the first level of children i.e.the contained collections is fetched along with the parent.
But when I execute a GET, I see that the entire tree is fetched.
setting max_fetch_depth does not make a difference.
Am I wrong somewhere here. If yes, please correct me.
-Poonam

http://www.hibernate.org/hib_docs/v3/re ... -manytoone

"[b]Note that single valued associations (many-to-one and one-to-one associations) do not support orphan delete.[/b]
"

So it will not delete and cascade.

Well this does not answer your problem but atleast lets you know that you will have to change the mapping. if this hepls please do rate.

As per the documentation you cannot delete without relation, so its mendatory for you to define one-to-many relation in parent table

Regards,

Rohit(Sagi)

we had the same problem we did it manually since we wanted a uni directional assosciation .....

Well, thanks for the suggestion subu......
if not without a collection then will a bidirectional one-to-may relationship work out.
I am just fighting with the following mapping:
<class name="xxx.ServerDetails"
lazy="false"
extends="xxx.Entity">
<key column="entityId" />
<property name="Name" column="Name" />

<set name="endPoints" table="SERVER_ENDPOINTS" lazy="false"
inverse="true"
cascade="all">
<cache usage="read-write"/>
<key column="entityId" />
<one-to-many
class="xxx.EndPointCapability"/>
</set>
</class>

<class name="xxx.EndPointCapability"
table="EndPointCapability" lazy="false">
<cache usage="read-write" />
<id name="endPointId" column="endPointId"></id>
<many-to-one name="serverDetails" column="serverDetails"
class="xxx.ServerDetails"
lazy="false" cascade="all" not-null="true"/>
<property name="ename" column="ename" />
</class>

Now I am using Spring HibernateTemplate,
Adding a Server autom automatically adds a EndPoint.


But, Delete of a Server does not automatically delete the EndPoint.
Code




Exception in thread "main" org.springframework.dao.DataIntegrityViolationException: Hibernate operation: could not delete: [xxx.ServerDetails#en1]; SQL [delete from ServerDetails where entityId=?]; Integrity constraint violation FKA6D55C8D4E0F4DE8 table: ENDPOINTCAPABILITY in statement [delete from ServerDetails where entityId=?]; nested exception is java.sql.SQLException: Integrity constraint violation FKA6D55C8D4E0F4DE8 table: ENDPOINTCAPABILITY in statement [delete from ServerDetails where entityId=?]
java.sql.SQLException: Integrity constraint violation FKA6D55C8D4E0F4DE8 table: ENDPOINTCAPABILITY in statement [delete from ServerDetails where entityId=?]
at org.hsqldb.jdbc.Util.throwError(Unknown Source)
at org.hsqldb.jdbc.jdbcPreparedStatement.executeUpdate(Unknown Source)
at org.apache.commons.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:101)
at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2296)
at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2442)
at org.hibernate.action.EntityDeleteAction.execute(EntityDeleteAction.java:73)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:248)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:232)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:144)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:297)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:985)
at org.springframework.orm.hibernate3.HibernateAccessor.flushIfNecessary(HibernateAccessor.java:394)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:367)
at org.springframework.orm.hibernate3.HibernateTemplate.delete(HibernateTemplate.java:788)

Now, I am not able to make out what the problem is .Can someone help.
How will the cascade delete work in case of a bidirectional one-to-many relationship.
-Poonam.

u have to set cascade-all,delete-orphan

u have to set cascade-all,delete-orphan

Well I am done.....got the solution to my problem.
Some credit does go to Sagi for pointing me to use the attribute not-found="ignore"
which helps to get rid of the DataIntegrityViolationException.
The mapping file for a bi-directional one-to-many relationship is as follows:

Here : things tested are :
1. adding a parent( with attahced child) add the child automatically. TestCode:


2. Delete a Parent deletes the child.(use cascade-"all" in the parent's set)


3. Delete a Child does not delete the parent( use not-found="ignore" in the parent's set)

I hope this link will be useful to those drenched in the cascade delete use-case.
Now, I am worried about my application performance. As a select of the root Object of my tree will fetch all contained objects. Well, dont want to discuss in the same topic.
Thanks to all those who attempted to help me.
-Poonam.