I have an entity like
@Entity
public class Address {
@Id
private int id;
private String street;
private String city;
private String state;
private String zip;
private Set<Address> addressSet = new HashSet<Address>();
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
...
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY,
mappedBy = "address")
public Set<Address> getAddressSet() {
return this.addressSet;
}
public void setAuthDevices(Set<Address> address) {
this.addressSet = address;
}
}
and entity :
@Entity
public class Student {
@Id
private int id;
private String name;
@ManyToOne(cascade=CascadeType.PERSIST)
Address address;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
...
}
if i [sic] do this :
Student emp = new Student();
emp.setId(1);
emp.setName("name");
Address addr = new Address();
addr.setId(1);
addr.setStreet("street");
addr.setCity("city");
addr.setState("state");
emp.setAddress(addr);
addr.getAddressSet().add(emp);
em.persist(emp);
the cascade attribute works and two insert are generated(cascade persist
works, but whenI do something like this :
Student emp = em.find(Student.class, 1L);
emp.setName("name");
Address addr = em.find(Adress.class, 1L);
addr.setStreet("streetOne");
emp.setAddress(addr);
em.persist(emp);
two sql updates are generates and address and student is updates, but
there is NO cascade = MERGE on Student entity... how is this POSSIBLE ?
annotations in the same class. Don't do that anyway.
You probably don't need to initialize 'Address#addressSet' explicitly. I'm
puzzled why people do that in entity classes. What does it provide?