[hibernate-issues] [Hibernate-JIRA] Created: (HHH-2101) Can't use outer join in table with composite-id, key-many-to-one

[Hugo Zhu (JIRA)]

Can't use outer join in table with composite-id, key-many-to-one
----------------------------------------------------------------

         Key: HHH-2101
         URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2101
     Project: Hibernate3
        Type: Improvement

  Components: core  
    Versions: 3.1.3    
 Environment: MYSQL: 5.0.15-nt-log
mysql-connector-java-3.0.16-ga
Hibernate 3.1.3
    Reporter: Hugo Zhu


MYSQL 5 database;

HBM like below: 
  <class name="Blog" table="blog" dynamic-update="true">
        <id column="id" name="id" type="long">
            <generator class="native"/>
        </id>
        ...
  </class>

  <class name="BlogUrl" table="blog_url" dynamic-update="true">
        <id column="id" name="id" type="long">
            <generator class="native"/>
        </id>
        <property name="url" type="string" length="255" not-null="true"/>
        <property name="urlHash" type="string" length="32" unique="true" not-null="true"/>
        <property name="numOfHits" type="integer"/>
        <property name="created" type="timestamp"/>
    </class>

    <class name="BlogUserUrl" table="blog_user_url" dynamic-update="true">
        <composite-id>
            <key-many-to-one name="url" class="BlogUrl"/>
            <key-many-to-one name="blog" class="Blog"/>
        </composite-id>
        <property name="title" type="string" length="255" not-null="true"/>
        <property name="description" type="string" length="255"/>
        <property name="created" type="timestamp"/>
    </class>

But:
getSession().createCriteria(BlogUserUrl.class).setFetchMode("url",FetchMode.JOIN).add(Restrictions.eq("blog", blog).setMaxResults(25).list();
Still generates 2 queries - query 1: query out BlogUserUrl, then query 2: possible 25 sub queries for earch BlogUrl

The better way should be just 1 outer join.

I have set: <property name="max_fetch_depth">1</property> in Hibernate configuration, but there is no join attribute in element: key-many-to-one.

The only way to solve this issue I can find out is:
HQL: select this,this.url from BlogUserUrl this where this.blog=?, but I have to add a loop in results to conver the Object[] list to BlogUserUrl only  list. Not ideal

Thanks for looking into this issue.
Hugo



-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
   http://opensource.atlassian.com/projects/hibernate/secure/Administrators.jspa
-
For more information on JIRA, see:
   http://www.atlassian.com/software/jira