Using natural-id in many-to-one relation

Rober2D2 · **Joined:** Tue Oct 30, 2007 7:57 am **Posts:** 47

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hibernate 3.0

I have mapped a many-to-one relation between 2 tables, using 2 different columns. Class EVNAmbito is the one part. To implement the relation, I declared a properties set, named idnatural.

Mapping documents:

Code:

<class name="EVNAmbito" table="TBREVTAMBITO" lazy="false" catalog="MAPEVN_PROP" mutable="false">
       <id name="id" type="string" column="CDAMBITO" length="16">
            <generator class="assigned" />       
       </id>

      <properties name="idnatural">      
          <many-to-one name="organismoDestino" class="EVNOrganismoDestino" column="CDORGANISMODEST" fetch="join" not-null="true" />       
          <many-to-one name="tipoAsunto" class="EVNTipoAsunto" column="CDTIPOASUNTO" fetch="join" not-null="true" />          
      </properties>
</class>

Code:

       <!-- Relación de sólo lectura. Necesaria para filtrar usando la lista de ámbitos permitidos al usuario -->
       <many-to-one name="ambito" class="EVNAmbito" property-ref="idnatural" insert="false" update="false" fetch="select">
          <column name="CDORGDESTINO"/>
          <column name="CDTIPOASUNTO"/>
       </many-to-one>

The thing, is that those 2 properties, form also the natural-id of the class, so I'd like to declare the natural-id, and use it for the relation, instead of the properties. The problem I have, is that I don't know how to refer two the natural-id in the many side. I tried with natural-id, naturalId, naturalid in the property-ref, but does not work. Code should be someting like:

Code:

<class name="EVNAmbito" table="TBREVTAMBITO" lazy="false" catalog="MAPEVN_PROP" mutable="false">
       <id name="id" type="string" column="CDAMBITO" length="16">
            <generator class="assigned" />       
       </id>

      <natural-id mutable="false">
          <many-to-one name="organismoDestino" class="EVNOrganismoDestino" column="CDORGANISMODEST" fetch="join" not-null="true" />       
          <many-to-one name="tipoAsunto" class="EVNTipoAsunto" column="CDTIPOASUNTO" fetch="join" not-null="true" />          
      </natural-id>
</class>

Code:

       <!-- Relación de sólo lectura. Necesaria para filtrar usando la lista de ámbitos permitidos al usuario -->
       <many-to-one name="ambito" class="EVNAmbito" property-ref="???????" insert="false" update="false" fetch="select">
          <column name="CDORGDESTINO"/>
          <column name="CDTIPOASUNTO"/>
       </many-to-one>

Is possible to do that?

palodan · **Posted:** Wed Dec 26, 2007 3:11 pm

Hi,
Can you please tell me what is the problem in gouping those many-to one eleements as properties?This <propertes ></Properties> tag is using only for grouping.even after grouping we can refer these many-to-one relation as like independent fields.

This is possible through formula join

<properties name="idnatural">
<many-to-one name="organismoDestino" class="EVNOrganismoDestino" column="CDORGANISMODEST" fetch="join" not-null="true" />
<many-to-one name="tipoAsunto" class="EVNTipoAsunto" column="CDTIPOASUNTO" fetch="join" not-null="true" />
</properties>

<many-to-one name="ambito" class="EVNAmbito" property- ref="idnatural" insert="false" update="false" fetch="select">
<formula>CDORGDESTINO</formul>
<formul>CDTIPOASUNTO"<formula/>
</many-to-one>

Rober2D2 · **Joined:** Tue Oct 30, 2007 7:57 am **Posts:** 47

It works perfectly with properties. I just wanted to make use of the natural-id property, because those two many-to-one inside the properties tag, make a perfect unique key.

So I wandered if it was possible to refer to natural-id in joins. If it isn't, no matter, I will keep using properties.