Need help with Hibernate? Read this first:
http://www.hibernate.org/ForumMailingli ... AskForHelp


Hi, I've a problem with a many-to-many mapping.
The scenario where I'm working in it's here:

Hibernate version: 3

Name and version of the database you are using: Oracle 9

Java jdk 1.5.0_09

First of all there is the hbm file of the tables that I've mapped:


Mapping documents:

Table Gruppi:

<hibernate-mapping>
<class name="com.tiengineering.webapp.users.orm.Gruppo"
table="TABGRUPPI" >

<id name="idgruppo"
type="java.lang.Integer"
column="IDGRUPPO"
unsaved-value="null">

<generator class="sequence">
<param name="sequence">IGruppi</param>
</generator>
</id>

<property name="nomegruppo"
type="java.lang.String"
column="NOMEGRUPPO"
not-null="true"
unique="true"
length="50" >
</property>
<property name="descrizione"
type="java.lang.String"
column="DESCRIZIONE" >
</property>

<!-- Associations -->

<!-- bi-directional many-to-many association to Tabgruppilivelli -->
<set name="livelli"
table="tabgruppilivelli"
lazy="false"
inverse="false"
cascade="all">
<key>
<column name="IDGRUPPO" not-null="true"/>
</key>
<many-to-many class="com.tiengineering.webapp.users.orm.Livello">
<column name="IDLIVELLO" not-null="true"/>
</many-to-many>
</set>


<!-- bi-directional many-to-many association to Tabutentigruppi -->
<set name="utenti"
table="tabutentigruppi"
lazy="false"
inverse="true"
cascade="none">
<key>
<column name="IDGRUPPO" not-null="true"/>
</key>
<many-to-many class="com.tiengineering.webapp.users.orm.Utente">
<column name="IDUTENTE" not-null="true"/>
</many-to-many>
</set>
</class>
</hibernate-mapping>


Table utente:
<hibernate-mapping>
<class name="com.tiengineering.webapp.users.orm.Utente"
table="TABUTENTI">

<id name="idutente"
type="java.lang.Integer"
column="IDUTENTE"
unsaved-value="null">

<generator class="sequence">
<param name="sequence">IUtenti</param>
</generator>
</id>

<property name="userid"
type="java.lang.String"
column="USERID"
not-null="true"
unique="true"
length="50">
</property>
<property name="fullname"
type="java.lang.String"
column="FULLNAME"
not-null="true"
length="200">
</property>
<property name="descrizione"
type="java.lang.String"
column="DESCRIZIONE">
</property>

<!-- Associations -->

<!-- bi-directional many-to-many association to Tabpermessispeciali -->
<set name="permessispeciali"
table="tabpermessispeciali"
lazy="false"
inverse="false"
cascade="all">
<key>
<column name="IDUTENTE" not-null="true"/>
</key>
<many-to-many class="com.tiengineering.webapp.users.orm.Livello">
<column name="IDLIVELLO" not-null="true"/>
</many-to-many>
</set>


<!-- bi-directional many-to-many association to Tabutentigruppi -->
<set name="gruppi"
table="tabutentigruppi"
lazy="false"
inverse="false"
cascade="all">
<key>
<column name="IDUTENTE" not-null="true"/>
</key>
<many-to-many class="com.tiengineering.webapp.users.orm.Gruppo">
<column name="IDGRUPPO" not-null="true"/>
</many-to-many>
</set>
</class>
</hibernate-mapping>

Table Livelli:

<hibernate-mapping>
<class name="com.tiengineering.webapp.users.orm.Livello"
table="TABLIVELLI" >

<id name="idlivello"
type="java.lang.Integer"
column="IDLIVELLO"
unsaved-value="null">

<generator class="sequence">
<param name="sequence">ILivelli</param>
</generator>
</id>

<property name="nomelivello"
type="java.lang.String"
column="NOMELIVELLO"
not-null="true"
unique="true"
length="100">
</property>
<property name="descrizione"
type="java.lang.String"
column="DESCRIZIONE">
</property>

<!-- Associations -->

<!-- bi-directional many-to-many association to Tabgruppilivelli -->
<set name="gruppi"
table="tabgruppilivelli"
lazy="false"
inverse="true"
cascade="none">
<!-- cascade="all" -->
<key>
<column name="IDLIVELLO" not-null="true"/>
</key>
<many-to-many class="com.tiengineering.webapp.users.orm.Gruppo">
<column name="IDGRUPPO" not-null="true"/>
</many-to-many>
</set>



<!-- bi-directional many-to-many association to Tabpermessispeciali -->
<set name="permessispeciali"
table="tabpermessispeciali"
lazy="false"
inverse="true"
cascade="none">
<!-- cascade="all" -->
<key>
<column name="IDLIVELLO" not-null="true"/>
</key>
<many-to-many class="com.tiengineering.webapp.users.orm.Utente">
<column name="IDUTENTE" not-null="true"/>
</many-to-many>
</set>

</class>
</hibernate-mapping>






When I try to save object Utente with a levels and groups it's ok, I've this insert result from hibernate after session.flush and commit of transaction:


The generated SQL (show_sql=true):

Hibernate: select IUtenti.nextval from dual
Hibernate: insert into TABUTENTI (USERID, FULLNAME, DESCRIZIONE, IDUTENTE) values (?, ?, ?, ?)
Hibernate: insert into tabpermessispeciali (IDUTENTE, IDLIVELLO) values (?, ?)
Hibernate: insert into tabpermessispeciali (IDUTENTE, IDLIVELLO) values (?, ?)
Hibernate: insert into tabutentigruppi (IDUTENTE, IDGRUPPO) values (?, ?)



To save Utente Object I use session.merge();
The problem is when I tried to save a Gruppo with levels:
when I made merge and flush hibernate make this

The generated SQL (show_sql=true):
Hibernate: select IGruppi.nextval from dual
Hibernate: insert into TABGRUPPI (NOMEGRUPPO, DESCRIZIONE, IDGRUPPO) values (?, ?, ?)
Hibernate: insert into tabgruppilivelli (IDGRUPPO, IDLIVELLO) values (?, ?)
Hibernate: insert into tabgruppilivelli (IDGRUPPO, IDLIVELLO) values (?, ?)



after commit of transaction make a delete and after reinsert in tabgruppilivelli

The generated SQL (show_sql=true):
Hibernate: delete from tabgruppilivelli where IDGRUPPO=?
Hibernate: insert into tabgruppilivelli (IDGRUPPO, IDLIVELLO) values (?, ?)
Hibernate: insert into tabgruppilivelli (IDGRUPPO, IDLIVELLO) values (?, ?)


Data persist in table tabgruppi livelli until I try to get list of guppi, because after querys hibernate make a delete on table gruppilivelli

The generated SQL (show_sql=true):
Hibernate: select utenti0_.IDGRUPPO as IDGRUPPO1_, utenti0_.IDUTENTE as IDUTENTE1_, utente1_.IDUTENTE as IDUTENTE0_0_, utente1_.USERID as USERID0_0_, utente1_.FULLNAME as FULLNAME0_0_, utente1_.DESCRIZIONE as DESCRIZI4_0_0_ from tabutentigruppi utenti0_, TABUTENTI utente1_ where utenti0_.IDUTENTE=utente1_.IDUTENTE(+) and utenti0_.IDGRUPPO=?
Hibernate: select livelli0_.IDGRUPPO as IDGRUPPO1_, livelli0_.IDLIVELLO as IDLIVELLO1_, livello1_.IDLIVELLO as IDLIVELLO5_0_, livello1_.NOMELIVELLO as NOMELIVE2_5_0_, livello1_.DESCRIZIONE as DESCRIZI3_5_0_ from tabgruppilivelli livelli0_, TABLIVELLI livello1_ where livelli0_.IDLIVELLO=livello1_.IDLIVELLO(+) and livelli0_.IDGRUPPO=?
Hibernate: delete from tabgruppilivelli where IDGRUPPO=?


so the data lost and there is no association between gruppi and livelli.
Someone can give me some hint to understand where the problem is?
Thank you for the help.


Problems with Session and transaction handling?

Read this: http://hibernate.org/42.html