save and saveOrUpdate problem

gbonnard · **Posted:** Tue Dec 16, 2003 8:51 am

Dear all,
I don't understand how to manage save and update.
Actually i would like to save value when there is no data for the key and update when any.

I use saveOrUpdate function but when there is not data, it crashes and if I use save function it crashes when there is data !

Moreover I use a string key and unsaved-value="null" for this key so it is strange ....

My mapping is as follows :

Code:

<hibernate-mapping>
   <class name="fr.gouv.finances.dgi.opale.commun.transverse.persistent.SirenPersistent" table="SIREN">
      <id name="numSiren" column="PK_NUM_SIREN" unsaved-value="null">
         <generator class="assigned"/>
      </id>
      <property name="entrepriseDge" column="APPARTENANCE_DGE" not-null="true"/>
   </class>
</hibernate-mapping>

gbonnard · **Posted:** Tue Dec 16, 2003 9:46 am

Nobody has an idea ?

emmanuel · **Posted:** Tue Dec 16, 2003 10:24 am

This is a FAQ.
http://www.hibernate.org/116.html#A11
and somewhere in the doc.

If using hibernate 2.1, you can use the <version unsaved-value="...">

gbonnard · **Posted:** Tue Dec 16, 2003 10:35 am

I agree but as I put unsaved-value="null" .. I do not understand why it is not possible to create a new row with saveOrUpdate when there is no data !!!

HELP

emmanuel · **Posted:** Tue Dec 16, 2003 10:46 am

You are using an assigned generator. Have a look at section 9.4. of the reference guide.

With Hibernate, you can't save an object with a null id in DB. This is not allowed and this would inconsistent with DB constraints.

gbonnard · **Posted:** Tue Dec 16, 2003 11:16 am

Ok so is there a way to check if the data are in the DB ? (except doing a select)

emmanuel · **Posted:** Tue Dec 16, 2003 11:26 am

Yes, several solutions :
- business rules allow you to know if it's a new object, then explicitly call save() or update() : not that good.
- business rules allow you to know if it's a new object, thus implement it in an interceptor isUnsaved(). Have a look at section 9.4
- use version or timestamp in your object, thus you can use a version unsaved-value. If the object has been saved, then version is not null, and Hibernate can know it. Note this is a 2.1 feature.