[nhibernate-issues] [NHJIRA] Commented: (NH-2704) Bidirectional one-to-one relation through FK (using property-ref) proxiable

[Boyan T. (JIRA) <nh...@gm...>]

    [ http://216.121.112.228/browse/NH-2704?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=21126#action_21126 ] 

Boyan Trushev commented on NH-2704:
-----------------------------------

I think we are in some sort of misunderstanding here...
So let me try to explain my idea with the example I gave in the test case from my first attachment. Let's have a Person entity which has one-to-one relation to an Employee:

<class name="Person">
  <id name="Id" type="int">
    <generator class="identity" />
  </id>
  <property name="Name"/>
  <one-to-one name="Employee" lazy="proxy"  property-ref="Person" fetch="select" />
</class>

public class Person
{
  	public virtual int Id { get; set; }
	public virtual string Name { get; set; }
	public virtual Employee Employee { get; set; }
}

When a person object is loaded from the database the following query is created:

SELECT
        person0_.Id as Id0_0_,
        person0_.Name as Name0_0_ 
    FROM
        Person person0_ 
    WHERE
        person0_.Id=@p0;

The Employee property should not be initialized on that stage. Now if the Employee property is accessed, the person proxy finds that the property is not initialized and produces a query like that to initialize it:

SELECT
        employee0_.Id as Id1_0_,
        employee0_.PersonName as PersonName1_0_,
        employee0_.Person as Person1_0_ 
    FROM
        Employee employee0_ 
    WHERE
        employee0_.Person=@p0;

@p0 is the person id. 

With the current NH version both queries are executed on loading of the person object - the Employee property is eagerly loaded. With the patch I proposed it works exactly as I described and IMHO this is the correct behavior. Hope it is now clear what I'm trying to explain and why I have opened the ticket.


> Bidirectional one-to-one relation through FK (using property-ref) proxiable
> ---------------------------------------------------------------------------
>
>                 Key: NH-2704
>                 URL: http://216.121.112.228/browse/NH-2704
>             Project:  NHibernate
>          Issue Type: Improvement
>          Components: Core
>    Affects Versions: 3.2.0Alpha3
>            Reporter: Boyan Trushev
>            Priority: Minor
>         Attachments: NH2704.patch, NH2704_fix.patch
>
>
> Hi, 
> In our project we use one-to-one relations that are not referencing same primary key, instead property-ref is used to specify the referenced property. In this case however we have noticed that lazy="proxy" doesn't work as expected - the "lazy" objects are eagerly loaded on loading of the parent objec

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