Cascading and Orphan Removal

Cascading

By default, an operation on a parent entity does not reach its related entities. Cascading passes the operation on. You set it with the cascade attribute.

Orphan Removal

orphanRemoval = true deletes a child row when the child is removed from the parent's collection. It fits relationships where the child cannot exist without the parent, such as order lines in an order.

@OneToMany(mappedBy = "department", cascade = CascadeType.ALL, orphanRemoval = true)
private List<Employee> employees = new ArrayList<>();

department.addEmployee(employee);
session.persist(department);

department.getEmployees().remove(employee);

Code Explanation:

• With CascadeType.ALL, persisting the department also persists the new employee.
• Removing the employee from the list makes it an orphan, and Hibernate deletes its row at flush.
• Deleting the department would also delete all its employees.

Use cascading only from a parent to children it owns. In Hibernate 7, the old Hibernate-specific types SAVE_UPDATE and DELETE no longer exist, so use the standard types above.