instance « Update « JPA Q&A

1. Will hibernate update the database when a persistence instance has been set but not changed?    stackoverflow.com

If I have an instance of a persistence object, and I set some members in like so:

MyThing thing = session.get(MyThing.class, id);
thing.setSomething(thing.getSomething());
session.update(thing);

2. Sample persistence.xml for a production instance using jpa2 and hibernate 3.6.x    stackoverflow.com

    <property name="hibernate.generate_statistics" value="true"/>

3. Startup problems with static instances of Persistent objects    forum.hibernate.org

We have a system where we make use of the HibernateSession and PersistentRootClass patterns. We have a number of Enum type of objects that we initialize from the database, but we are facing a recursion problem during startup. Here is an example of one of the Enum classes Code: public final class EnumType extends PersistentEnum implements Serializable, Comparable { ...

4. How to access the EntityPersister for a persistent instance?    forum.hibernate.org

Hibernate version: 2.1.6 How can I access the EntityPersister for a persistent instance? I can get the ClassMetadata for the class via SessionFactory.getClassMetaData(Class) and cast the returned value to an AbstractEntityClass, but I don't like "casting on faith". The ultimate objective is to get a handle on the IdentifierGenerator for the instance's persistent class. For this class, I want to sometimes ...

5. Persisting an interface instance?    forum.hibernate.org

I'm trying to persist an instance of an interface without knowing the implementation. I've created a Hibernate mapping file for the interface and the appropriate database table is created successfully. Unfortunately, when I try to persist the object, Hibernate throws the following exception: "No persister for: {interface implementation}" This occurrs because it attempts to look up the Persister for the specific ...

6. Duplicate persistent instances    forum.hibernate.org

7. saveOrUpdate and ignoring persistent instance    forum.hibernate.org

Query query = session.getNamedQuery( hsql ); prepareQuery( query, names, values ); Event event = ( Event) query.uniqueResult(); event.setFlag( true ); ...

8. Incorrect instance reference saved    forum.hibernate.org

Hibernate version: 3.1 ..beginTransaction(); MySmallObject localRef new MySmallObject(); // holds a collection session.save(localRef); MyOtherObject localRef2 = new MyOtherObject(); localRef2.setProperty(localRef) session.save(localRef2); // reusing the MySmallObject declaration above!! localRef = new MySmallObject(); // holds another collection session.save(localRef); // reusing the OtherObject declaration above!! localRef2 = new MyOtherObject(); localRef2.setProperty(localRef); session.save(localRef2); ..commit(); The strange effect that happens: All collectioins of localRef (for both instances) get ...

9. Error persisting a simple object : object is not an instance    forum.hibernate.org

Author Message marciobarroso Post subject: Error persisting a simple object : object is not an instance Posted: Sun Oct 29, 2006 8:54 pm Newbie Joined: Wed Apr 05, 2006 5:27 pm Posts: 6 Location: SP - BR Need help with Hibernate? Read this first: http://www.hibernate.org/ForumMailingli ... AskForHelp Help me ... I tried everything what I could but I did ...

10. How to correctly remove shared instances?    forum.hibernate.org

Hi all, I have a many-to-many mapping between InitialStateType and Position and a one-to-many mapping between ActionsType and Position. Both mappings are unidirectional. A row in Position can be shared by InitialStateType and ActionsType (both lists have a reference on the same object in Java). Everything works fine except when I try to delete an instance of InitialStateType or ActionsType. I ...

11. begginer persisting an instance    forum.hibernate.org

Hello, I'm kind of a begginer with hibernate and I have a "problem" when I persist an object. I have the following mapping: Code: ...