I don't understand why this code retrieve only one document from the category:

public void execute() {
Transaction tx = null;
Category category = null;

try {
int categoryID = 3;

Session session = HibernateUtil.currentSession();
tx = session.beginTransaction();

category = (Category) session.get(Category.class,
new Long(categoryID));
Hibernate.initialize(category.getDocuments());

tx.commit();
} catch (HibernateException he) {
try {
tx.rollback();
} catch (HibernateException he2) {
he2.printStackTrace();
}

he.printStackTrace();
} finally {
try {
HibernateUtil.closeSession();
} catch (HibernateException he) {
he.printStackTrace();
}
}

System.out.println(category.getName());

Iterator iterator = category.getDocuments().iterator();

while (iterator.hasNext()) {
Document doc = (Document) iterator.next();
System.out.println(doc);
}
}


result is:

the name of category
the id of a document

Instead in my document table there are 3 document with category_id=3.

Here is the mapping for category:

<?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="model.Category" table="category">
<id name="id" column="category_id" type="long" unsaved-value="null">
<generator class="native"/>
</id>
<property name="name" type="string"/>
<property name="description" type="string"/>

<set name="children">
<key column="category_id"/>
<one-to-many class="model.Category"/>
</set>

<many-to-one name="parent" column="parent_id" class="model.Category" cascade="none"/>

<set name="documents" inverse="true" cascade="save-update" lazy="true">
<key column="document_id"/>
<one-to-many class="model.Document"/>
</set>
</class>
</hibernate-mapping>


The mapping for Document instead is:

<?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="model.Document" table="document">
<id name="id" column="document_id" type="long" unsaved-value="null">
<generator class="native"/>
</id>
<property name="name" type="string"/>
<property name="description" type="string"/>
<property name="text" type="text"/>
<many-to-one name="category"
class="model.Category"
column="category_id"
not-null="true"/>
</class>
</hibernate-mapping>


So the problem is that session.get retrieve only one document, instead it should retrieve 3 documents. Why?

what about the generated sql? is it right?

i post it...but i don't understand it...it is not much readable! (is it normal?)


[main] Hibernate: select category0_.category_id as category1_1_, category0_.name as name1_,
category0_.description as descript3_1_, category0_.parent_id as parent_id1_, category1_.category_
id as category1_0_, category1_.name as name0_, category1_.description as descript3_0_, category1_
.parent_id as parent_id0_ from category category0_ left outer join category category1_ on categor
y0_.parent_id=category1_.category_id where category0_.category_id=?
[main] Hibernate: select children0_.category_id as category1___, children0_.category_id as c
ategory1_1_, children0_.name as name1_, children0_.description as descript3_1_, children0_.parent
_id as parent_id1_, category1_.category_id as category1_0_, category1_.name as name0_, category1_
.description as descript3_0_, category1_.parent_id as parent_id0_ from category children0_ left o
uter join category category1_ on children0_.parent_id=category1_.category_id where children0_.cat
egory_id=?
[main] Hibernate: select documents0_.document_id as document1___, documents0_.document_id as
document1_2_, documents0_.name as name2_, documents0_.description as descript3_2_, documents0_.t
ext as text2_, documents0_.category_id as category5_2_, category1_.category_id as category1_0_, c
ategory1_.name as name0_, category1_.description as descript3_0_, category1_.parent_id as parent_
id0_, category2_.category_id as category1_1_, category2_.name as name1_, category2_.description a
s descript3_1_, category2_.parent_id as parent_id1_ from document documents0_ left outer join cat
egory category1_ on documents0_.category_id=category1_.category_id left outer join category categ
ory2_ on category1_.parent_id=category2_.category_id where documents0_.document_id=?

copy paste the second query into db client and check number of rows returned

only one row returned!
So the sql is wrong...but i don't know why...and i am frustrated because this should be a very common and simple operation!

<key column="document_id"/>

are you sure of this?

Ehehe, sorry!
I have corrected it now and everything is ok!
Thanks!