Question about "left join fetch"

nerotnt · **Joined:** Wed Oct 08, 2003 10:31 am **Posts:** 247

It's kind of strange the following situation, I think. When we have a collection that's loaded "lazy", like the documentation says, we use a "left join fetch" to load the "set". The 1) example works but the 2) doesn't by giving me the following error:

Code:

java.lang.ClassCastException

Did I miss something?
Can someone please explain me this point?

Here's the two examples:
1)

Code:

res = session.find(
      "select he " +
      "from vo.Ensaio e " +
      "left join e.historicoEnsaios he where e.tabela = ?",
      tabela,
      Hibernate.STRING
);

2)

Code:

res = session.find(
      "select he " +
      "from vo.Ensaio e " +
      "left join [b]fetch[/b] e.historicoEnsaios he where e.tabela = ?",
      tabela,
      Hibernate.STRING
);

-----------------------------------------------------
Mapping file (generated with Middlegen R3)
-----------------------------------------------------
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >

<hibernate-mapping>


<class
name="vo.Ensaio"
table="ensaio"
>

<id
name="id"
type="long"
column="id"
>
<generator class="increment" />
</id>

<property
name="referencia"
type="java.lang.String"
column="referencia"
not-null="true"
length="-1"
/>



<set
name="historicoEnsaios"
lazy="true"
inverse="true"
>
<key>
<column name="ensaio_fk" />
</key>
<one-to-many
class="vo.HistoricoEnsaio"
/>
</set>

</class>
</hibernate-mapping>

michael · **Posted:** Thu Dec 25, 2003 6:11 pm

Please post a complete Stack Trace of the Exception

emmanuel · **Posted:** Mon Dec 29, 2003 6:30 am

Actually the fetch is useless : you explicitly asked the return of the collection.