[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-3891) one-to-one with property-ref always non-lazy

[Sandeep Vaid (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-3891?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=33107#action_33107 ] 

Sandeep Vaid commented on HHH-3891:
-----------------------------------

Diego,
  I read the links provided by you.. but i have some more to day :)

  Consider this scenatio :
    I have one-to-one relation between Product and ProductBasic BUT at database level i have one-to-many between 
    PRODUCT and PRODUCTBASIC tables as history is mainted in the same table :
    
    PRODUCT ----> PID (PK)
    PRODUCTBASIC ---> PID (FK), USECODE , STARTTIMESTAMP forms Composite-key
    			
    PRODUCT
     PID	PNAME	
      1		Pen
    
    PRODUCTBASIC
     PID 	USECODE		STARTTIME		ENDTIME
     1		  100	       06-MAY-2009 11:00	07-MAY-2009 10:00
     1		  100	       07-MAY-2009 10:00	31-DEC-9999 00:00
     
     Now while querying for ProductBasic, i will always fetch the row which satisfies the condition STARTTIME<CURRENTTIME<ENDTIME
     and this will surely return me only one row.
     
     Ideally the generated sql query should be :
     
     select * from  PRODUCT product  left outer join PRODUCTBASIC productbasic  on '100'=productbasic.USETYPE 
        and product.PID=productbasic.PID 
        and (
         productbasic.STARTTIME<'09-MAY-2009 10:00' 
         and '09-MAY-2009 10:00'<productbasic.ENDTIME
        ) 
      where
  product.PID='1'
  
  PLEASE NOTE THAT i am not using the composite-key to establish the relationship. Instead i am using 
  
  1) product.PID=productbasic.PID
  2) productbasic.USETYPE='100'
  3) productbasic.STARTTIME<'09-MAY-2009 10:00' and '09-MAY-2009 10:00'<productbasic.ENDTIME
  
  This last condition can only be provided at runtime as we will get the currenTime value at runtime only.
  Now, if we allow productBasic to be fetched non-lazyly compulsary, it will form the query using only 1) & 2) conditions
  and it will not take condition 3) as it is not provide in .hbm.xml file.. 
  The incorrect query thus formed will be 
   select * from  PRODUCT product  left outer join PRODUCTBASIC productbasic  on '100'=productbasic.USETYPE 
      and product.PID=productbasic.PID  where product.PID='1'
      
      This incorrect query will fetch more than one rows and throw an error:
      org.hibernate.HibernateException: More than one row with the given identifier was found: for class ProductBasic.
      
      
   So now 2 things are must needed
    1) one-to-one with property-ref should be allowed to be loaded lazily.
    2) one-to-one should allow the use of filters (so that runtime conditions can be specified, 3) condition in my case)
  



> one-to-one with property-ref always non-lazy
> --------------------------------------------
>
>                 Key: HHH-3891
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3891
>             Project: Hibernate Core
>          Issue Type: Bug
>          Components: core
>            Reporter: Sandeep Vaid
>            Assignee: Diego Plentz
>
> I have one-to-one relationship betnwee Product and ProductBasic.
>   <one-to-one name="productBasic" cascade="save-update" property-ref="activeProduct" lazy="proxy">
>     <formula>'1'</formula>
>     <formula>PRODUCTID</formula>
>  </one-to-one>
>  
>  
>  ProductBasic.hbm.xml as :
>  <properties name="activeProduct">
>    <property  name="Code" column="CODE"></property>
>    <property  name="pId" column="PID" insert="false" update="false"></property>
>   </properties>
>   
>   
>   When i am using property-ref, and try to load Product, it eagerly fetches ProductBasic also as :
>   
>   select *
>   from PRODUCT productbo0_ left outer join PRODUCTPERIOD productbas1_ on '18'=productbas1_.CODE and productbo0_.PID=productbas1_.PID where productbo0_.PID=?
>   
>  NOTE: Along with Product, ProductBasic is also fetched in a single query.
>  
>  Even if i add constrained="true" in one-to-one mapping, the query gets fired as :
>   select * from PRODUCT productbo0_ where productbo0_.PID=?
>   select * from PRODUCTBASIC productbas0_ where productbas0_.CODE=? and productbas0_.PID=?
>   
>   NOTE: Along with Product, ProductBasic is also fetched in a different query.
>   
>   BUT in both these cases, ProductBasic is fetched always (non-lazy)..
>   
>   How can i fetch ProductBasic in a Non-Lazy manner in this case.

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