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

[Justin Forder (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-817?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=34591#action_34591 ] 

Justin Forder commented on HHH-817:
-----------------------------------

I ran into this today, using Java DB. I tested interactively against Java DB and MySQL to confirm that aliases didn't work in the WHERE clause, then found the MySQL documentation explaining that the SQL standard does not permit the use of aliases here.

http://dev.mysql.com/doc/refman/5.0/en/problems-with-alias.html

I found this discussed in various threads on the Hibernate User forum.

Initially I worked around the problem using an SQL restriction, but then I found the advice here:
http://stackoverflow.com/questions/84644/hibernate-query-by-example-and-projections/960278#960278

that using "this.property" works. It does, indeed, work for me, but leaves the worry that this (undocumented, so far as I know) behaviour may change in future.

I've added a comment to this forum thread:
https://forum.hibernate.org/viewtopic.php?f=1&t=988049&p=2421106#p2421106

-- Justin Forder

> 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, HHH-817_3.3.2GA_17882.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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