Hibernate and equals ()

Question

Perhaps I read somewhere that:

• Hibernate does not write to the database if the entity to be saved does not have any changes in its constant state in the database.
• Hibernate uses the equals () object to determine if it contains any changes in its state.

Can anyone confirm or deny them?

Also, is any of them applicable to the JPA specification?

Answer 1

• It is correct if the object is loaded into the same sleep mode session. (If the object was loaded in a previous session and was re-associated with the current one, hibernate no longer has the old state for comparison and gives an update just in case).

• Hibernate , , hibernate, , , . equals. Equals . ( " " ). :

  • org.hibernate.event.def.DefaultFlushEntityEventListener.dirtyCheck
  • org.hibernate.type.TypeFactory.findDirty

Answer 2

, Hibernate , , .

Hibernate equals . .

Answer 3

, .

equals() , .. , , , /. , , , Hibernate , , UPDATE ( SELECT , UPDATE)

Answer 4

1). Hibernate  - New Entity: id . , .  - : id null, . hibernate , - ( ), , .

2). equals, . , , , , , equals.

. http://docs.jboss.org/hibernate/orm/4.1/manual/en-US/html/ch04.html#persistent-classes-equalshashcode