One to one relationship in jpa

Question

I have two relation table like , I would Like to try select by UID by JPA ,
select *from student as P, Address as A where P.UserId=A.UserId
and A.UpdateId=uid;
step one
I have my persistence.xml testing by single table
step two I have two entity class from DB
in my student{} @Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Basic(optional = false)
@Column(name = "UserId", nullable = false)
private Integer userId;.....
in my address I have
@JoinColumn(name = "UserId", referencedColumnName = "UserId", nullable = false)
@OneToOne(cascade=CascadeType.ALL, mappedBy="Student")
private Student student;
what else I need to do in order to let it work??

Answer 1

jsutherl wrote:
To do a join in JPA you can either use "join" or the "." notation for a OneToOne.
i.e.
Select s from Student s where s.address.updateId = :id
You would need a OneToOne from Student to Address for this.
@OneToOne(mappedBy="student")
private Address address;
James : http://www.eclipselink.org
I guest I get the part that you post , but if I want to display the information out of two tables, but in Servlet
Query query=em.createNamedQuery("?");
List stList=query.getResultList();
Iterator stIterator=stList.iterator();
while(stIterator.hasNext()){
*? which class?*=?.stIterator.next();} ??
Thank you!