What is the meaning of the CascadeType.ALL for a @ManyToOne JPA association

In a JPA entity relationship, the CascadeType.ALL annotation specifies that all operations (persist, merge, remove, refresh, and detach) that are performed on the parent entity should be cascaded to the child entity.

For example, consider the following entities:

@Entity
public class Employee {
  @Id
  private Long id;
  
  @ManyToOne(cascade = CascadeType.ALL)
  private Address address;
  
  // other fields and methods
}

@Entity
public class Address {
  @Id
  private Long id;
  
  // other fields and methods
}

Here, the Employee entity has a many-to-one relationship with the Address entity. The CascadeType.ALL annotation on the address field specifies that all operations performed on an Employee entity should be cascaded to its associated Address entity.

For example, if an Employee entity is persisted, merged, or removed, the associated Address entity will be persisted, merged, or removed as well.

Cascading operations can be useful in cases where you want to ensure that the child entity is always in a consistent state with the parent entity. However, be careful when using cascading operations, as they can result in unintended side effects if not used correctly.