For instance selecting just the fields you need is relatively simple with JPQL:
SELECT i.url FROM Image i WHERE i.id = ...Developers look like JSON looks like, what we send to browser, what formatting it has, validation and size of JSON data, as it's easy to monitor and trim.
Can't say the same about Hibernate. How the hell even hibernate caching works? Why even are there 2 levels of Hibernate cache? It's too easy to create and abuse transactions. Dirty-checking is JUST WAYYYY TOOO EAZY TO ABUSE. not calling, using setter of an instance shouldn't update in database by default omg, It shouldn't be possible for transactions to leak outside some easily specified scope - I've seen one project where transaction leaked to Jackson!! Jackson was calling getters on fields and executing DB queries. JSON ended up as 2.6Mb instead list of 10 fields.
Hibernate is popular because we don't need to learn SQL to get needed data, but it's also super hard to get it right and don't do something stupid by accident.
If in any doubt, refer to JOOQ - it's the SQL-oriented ORM for Java.
https://docs.jboss.org/hibernate/stable/orm/userguide/html_s...
> using setter of an instance shouldn't update in database by default omg
This doesn't happen.. the database won't update until you ask the entity manager to persist the entity.
> I've seen one project where transaction leaked to Jackson!! Jackson was calling getters on fields and executing DB queries. JSON ended up as 2.6Mb instead list of 10 fields.
I suspect you might not agree, but JPA lazy loading is one of the easiest concepts to understand. However, I'd argue that leaking your database models to the view is a mistake to begin with and said application is already incorrect.
> If in any doubt, refer to JOOQ - it's the SQL-oriented ORM for Java.
Both the author/maintainer of jOOq and Hibernate agree that each has their place.
I really am amazed at developers that don't take the time to learn about the tools they use.
Doesn't this happen through automatic dirty checking?
Obviously JPA knows what fields were updated via dirty checking.. that's almost half the point of an ORM.
SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Person person = session.load(Person.class, 2); //loads Person object for id 2
person.setAge(32);
tx.commit();
session.close();
HibernateUtil.closeSessionFactory();
[1] - https://learnjava.co.in/automatic-dirty-checking-in-hibernat...
[1] - https://www.objectdb.com/java/jpa/persistence/update
[2] - https://stackoverflow.com/a/8307991
[3] - https://docs.oracle.com/javaee/6/tutorial/doc/bnbqw.html#bnb...
EDIT: Oops I accidentally replied to this twice
That is not how Hibernate or JPA is used normally. It is going out of standard way to achieve the thing you complain about.
I'm aware that that what occurs. That is my point. I'm responding to the previous posts statement "No calling a setter on an Entity doesn't automatically issue an sql UPDATE query". This is an example where calling a setter causes an update query to be run.
> That is not how Hibernate or JPA is used normally. It is going out of standard way to achieve the thing you complain about.
What about this not not how Hibernate and JPA are used normally? Are you saying that setters are not normally used? Do you mean that people normally call update or merge to persist an Entity? If so, I agree that is what people normally do. However, when people do that they tend to accidentally introduce bugs. Usually this occurs when they update an entity and then do some validation on it. When the validation fails they think they can avoid sending he changes to the DB by doing nothing. However, that isn't true. They have to manually evict the entity from the session to prevent that from happening.
So in all project I have seen, calling setter did not changed database.
> Do you mean that people normally call update or merge to persist an Entity?
Yes, people normally call update and merge to persist an entity.
Dog rex = em.find(Dog.class,"rex"); // 1
rex.setAge(2); // 2
// other query // 3
I think this is plain wrong, or I might have been very lucky with who I work with: if anything I think most people I work with learned JPA or other ORMs long after learning SQL.
Hibernate is how to get data into Java. And we still have database scripts, migrations to new versions and what not.
I saw a similar problem with some old codebase where I work. There is some Velocity templates that shows information stored on database entities (yeah... bad idea). And sometimes, we got some mysterious errors about transaction closed. Well... Results that Velocity calling the getters of these beans, can trigger a JPA/Hibernate query to get some additional data that has been loaded before. And this could happens after we close the database transaction.
There has to be ways around that though, perhaps using a duplicated domain of DTOs or coercing the ORM to use constructors or private setters to keep encapsulation and invariants.
Value classes like @Entity shouldn't have the responsibility to enforce those business rules.
We can disagree on which way is more object oriented though.