JPA CascadeType.PERSIST triggers persist even if the parent is not persisting-CodePudding

My problem is my application "works" although it shouldn't (AFAIK)

Every tutorial says that CascadeType.PERSIST causes a child to be persisted automatically when his parent is persisted. And it is usually followed by an example with explicit em.persist(parent)

My code looks like this (simplified):

@Entity
class Parent(
    @OneToMany(cascade = [CascadeType.PERSIST])
    val children: List<Child>
)

fun addChild() {
    val parent = parentRepository.find(id)
    val child = new Child()
    parent.children.add(child)
    // childRepository.save(child) is missing here but surprisingly the child is persisted
}

It seems CascadeType.PERSIST is triggered when the parent's collection is modified. Is it right? (I am using Hibernate 5.6.8, Spring 5.3.19 and Spring Data 2.6.4)

CodePudding user response：

This is the correct behavior according to section 3.2.4 of the JPA specification, covering discovering changes during synchronization to the database:

If X is a managed entity, it is synchronized to the database.

For all entities Y referenced by a relationship from X, if the relationship to Y has been annotated with the cascade element value
cascade=PERSIST or cascade=ALL, the persist operation is applied to Y.