How to Force JOIN on JPA EAGER FETCH

[jpa365]

Hi All,

I am using struts2.11-spring(2.5)-jpa(hibernate 3.2.5) combination.

I have a @ManyToOne annotation which eagerly fetched. I am unable to force join on this no matter what i do. it issues a seperate select statement once I make fetch type is set to Eager.

here 's the code

@Entity
@Table(name = "person")
public class Person {

@Id
@Column(name = "id", nullable = false)
private Long id;

@Column(name = "FirstName", nullable = false)
private String firstName;

@Column(name = "LastName", nullable = false)
private String lastName;

@ManyToOne(fetch=FetchType.EAGER)
@JoinColumn(name = "addressid", referencedColumnName = "addressid")
private Address address;

setters .. getters..

@Entity
@Table(name = "address")
public class Address {

@Id
@Column(name = "addressid", nullable = false)
private Integer addressid;

@Column(name = "StreetName", nullable = false)
private String streetName;

@Column(name = "HouseNumber", nullable = false)
private String houseNumber;
....

I tried hibernate specific annotation @Fetch(FetchMode.JOIN) , but still a separate query is excuted instead of joining person table and address table.
i can make this LAZY connection and do a JOIN FETCH but i want to Eagerly fetch but using a join. the reason for this is i am using

<filter>
<filter-name>Spring OpenEntityManagerInViewFilter</filter-name>
<filter-class>
org.springframework.orm.jpa.support.OpenEntityMana gerInViewFilter
</filter-class>
</filter>

in web.xml for getting all lazy collections on demand from Action/JSP even after transcation has been completed.

if i make my addess fetch LAZY this filter would generate a separate SQL and JOIN FETCH would go wasted.


"select p FROM Person p" generates the following

hibernate SQL:

Hibernate: select person0_.id as id1_, person0_.addressid as addressid1_, person0_.FirstName as FirstName1_, person0_.LastName as LastName1_ from person person0_

Hibernate: select address0_.addressid as addressid0_0_, address0_.City as City0_0_, address0_.HouseNumber as HouseNum3_0_0_, address0_.State as State0_0_, address0_.StreetName as StreetName0_0_, address0_.ZipCode as ZipCode0_0_ from address address0_ where address0_.addressid=?


Thanks in advance

[seenaka]

This is really a JPA and implementation issue, so I'm going to post the question to those forums, but I was curious if anyone had any luck looking at what jpa365 had posted back in December?

[rumberomelo]

Hello

Hibernate seems dont understand automatically the eager fetch

try with this select

select p FROM Person p left join fetch p.address

good luck