(versions:
Hibernate 3.2
annotations 3.3.0
entityManager 3.3.1
)

Hi,

I have a class just like that:

public class TbPessoa{
@LazyToOne(LazyToOneOption.NO_PROXY)
@Fetch(FetchMode.SELECT)
@OneToOne(fetch=FetchType.LAZY, optional=true,mappedBy="pessoa")
private TbUsuario tbUsuario;
}

and a
public class TbUsuario{
@JoinColumn(name = "ID_PESSOA", referencedColumnName = "ID_PESSOA")
@OneToOne(fetch=FetchType.LAZY)
private TbPessoa pessoa;
}

But there is nothing that I do to make the relation LAZY.
Every time I find a TbPessoa, the TbUsuario is selected too.

How can I do a lazy one-to-one then?

The 2 classes have default public constructors.
I already tried LazyToOneOption.NO_PROXY and LazyToOneOption.PROXY

My persistence.xml:
<property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect"/>
<property name="hibernate.show_sql" value="true"/>
<property name="hibernate.format_sql" value="true"/>
<property name="hibernate.default_schema" value="dbcorporativo"/>
<property name="hibernate.generate_statistics" value="true"/>
<property name="hibernate.use_sql_comments" value="true"/>

I forgot to mention:

TbPessoa{
@Id
@Column(name = "ID_PESSOA", nullable = false)
private String idPessoa;
}

and the ID_PESSOA on TbUsuario is a foreign key.
The key of TbUsuario is
@Id
@Column(name = "ID_USUARIO", nullable = false)
private String idUsuario;

and the gets/sets is there too.

thanks

thank you for your answer.

"if your B->C mapping is mandatory (constrainted=true), Hibernate will use proxy for C resulting in lazy initialization."
I think it means that, when I put the optional=false, Hibernate will use lazy.

But, even when I put optional=false
@OneToOne(fetch=FetchType.LAZY, optional=false,mappedBy="pessoa")
the TbUsuario IS queried...

what to do then?

But as I mentioned, it is not working...
:(

http://java.sun.com/javaee/5/docs/api/j ... #optional()
Whether the association is optional. If set to false then a non-null relationship must always exist.

When you use the option (optional = false), means the items is required mandatory by the object, you have to use (optional = true).

The document link mentioned previously says, you cannot have LazyLoading for a one-to-one, as the object WILL BE required by Hibernate,



Also why do u want to lazy load it? Is it a blob that u cannot afford to eager load?

I can do a EAGER fetch but I don't want to cause of performance problems (it didnt have a LOB, but is from a table very large and I dont need it)

What I mean is that, when I put optional=false (mandatory), "Hibernate will use a proxy" and then I get lazy loading.

But the lazy is not working even when I put optional=false (mandatory).

Thanks.

Can you paste the POJOs with hbms

I don't think it can conceptually work when used on the mappedBy side

The doc says even if u try to lazy load it'll still load (one-to-one) cos if a field and get/set exist for it, hibernate will try to put an object value for it, and if not the real object the proxy will be loaded. Which it either ways will query and fetch.

So technically we don't/cannot have lazy loading in a one-to-one case.

I don't quite understand the reasoning, but clearly the conclusion is wrong :) Check the wiki page talking about one to one and lazy loading.

What do you mean by that?

because a OneToOne(mappedBy) need to read the value of the PK from the mappedBy property, hence the other side has to be loaded.

this explains how to lazy load a one to one association using a purely hibernate implementation. How do you do this in JPA with Hibernate? How do you define a mandatory one to one mapping in jpa?

TIA