[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-817) Aggregate projection aliases should not be applied to where-clause

[David (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-817?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=32861#action_32861 ] 

David commented on HHH-817:
---------------------------

this bug is especially potent because it's the recommended technique for avoiding lazy-loaded properties!  

http://www.hibernate.org/hib_docs/reference/en/html/performance.html
" A different (better?) way to avoid unnecessary column reads, at least for read-only transactions is to use the projection features of HQL or Criteria queries. This avoids the need for buildtime bytecode processing and is certainly a preferred solution. "


If lazy-loading is the most requested feature, like the documentation says, and if people are expected to use the ProjectionList behavior in criteria searches to avoid loading their blobs, etc...  It's crazy this hasn't been fixed.  For everything that hibernate does, I'm really surprised someone hasn't addressed this massively basic use case.  I shouldn't have to create two tables and two classes because of one simple column.

> Aggregate projection aliases should not be applied to where-clause
> ------------------------------------------------------------------
>
>                 Key: HHH-817
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-817
>             Project: Hibernate Core
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 3.0.5
>         Environment: Oracle 9.2.0.6, Hibernate 3.0.5, Spring Framework 1.2.2 based application working on Jakarta Tomcat 5.0.28
>            Reporter: Michal Jastak
>            Priority: Minor
>         Attachments: HHH-817.patch
>
>
> following java code:
> protected Entity loadEntityLightweight(Serializable entityId) throws DataAccessException {
>     Criteria criteria = getSession().createCriteria(Entity.class);    
>     ProjectionList projectionList = Projections.projectionList();
>     projectionList.add(Property.forName(BaseEntity.PROP_ID), BaseEntity.PROP_ID);
>     projectionList.add(Property.forName(BaseEntity.PROP_TYPE), BaseEntity.PROP_TYPE);
>     criteria.setProjection(projectionList);
>     criteria.add(Restrictions.eq(BaseEntity.PROP_ID, entityId));
>     criteria.setResultTransformer(new AliasToBeanResultTransformer(Entity.class));
>     return (Entity) criteria.uniqueResult();
>   }
> generates following SQL query:
> select this_.id as y0_, this_.type as y1_ from entities this_ left outer join facilities this_1_ on this_.id=this_1_.id left outer join users this_2_ on this_.id=this_2_.id left outer join addresses address2_ on this_.address_id=address2_.id left outer join entities entity3_ on this_2_.employer_id=entity3_.id left outer join facilities entity3_1_ on entity3_.id=entity3_1_.id left outer join users entity3_2_ on entity3_.id=entity3_2_.id where y0_=?
> y0_ = ? expression in where clause is causing a 904 error on Oracle 9:
> ORA-00904: "Y0_": invalid identifier
> hibernate dialect: org.hibernate.dialect.Oracle9Dialect
> mapping for Entity class:
> <?xml version="1.0"?>
> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
>                                    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
> <hibernate-mapping default-lazy="false" default-cascade="save-update">
>  
>   <class name="Entity" table="entities" mutable="true">
>     <id name="id" type="java.lang.Long" unsaved-value="null">
>       <generator class="sequence">
>         <param name="sequence">entities_id_seq</param>
>       </generator>
>     </id>
>     <many-to-one  name="address"   class="Address" column="address_id" />
>     ...
>     <!--
>       -  Facilities
>       -->
>     <joined-subclass name="Facility" table="facilities">
>       <key column="id" />
>       ...
>       <set name="users" inverse="true" lazy="true">
>         <key column="facility_id" />
>         <one-to-many class="User" />
>       </set>
>     </joined-subclass>
>     <!--
>       -  Users
>       -->
>     <joined-subclass name="User" table="users" dynamic-insert="true" dynamic-update="true">
>       <key column="id" />
>       <many-to-one name="employer"   class="Entity"  column="employer_id" cascade="none" />
>       ...
>       <set name="userAuthorities" inverse="true" cascade="all-delete-orphan">
>         <key          column="user_id" />
>         <one-to-many  class="Authority" />
>       </set>
>     </joined-subclass>
>   </class>
> </hibernate-mapping>

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