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Many to one, one to many

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Tobiascapin

Post subject: Many to one, one to many

Posted: Mon Dec 07, 2009 5:29 am

Newbie

Joined: Mon Dec 07, 2009 5:09 am
Posts: 3

Hello,
I have a trouble with HB, I hope someone can help me...

I have 2 entities: Files and Details with relation One File -> Many Details.
First of all I would like to know if it is necessary to set in HB mappings the one to many Set in "Files" entity java object and also the many to one Object in "Details" entity java object.

My trouble is that sometimes (not always) when I save a new File with a new Details but with a Detail identical to an existing one the new File is created with not the Details, the Details reference of the existing one is updated referencing to the new File... i can no explain it very well, i try with an example:

Existing data in DB:
File(id: 1, name: Foo) -> Details (id:1, files: 1, string: Test)

I create new Object:
File(id: ?, name: Bar) -> Details (id:?, files: ?, string: Test)

Hibernate is set to get the new ids from the Oracle Sequences.
When i saveOrUpdate the File object this happend:
insert: File(id: 2, name: Bar)
update: Details (id:1, files: 1, string: Test) to Details (id:1, files: 2, string: Test)

So the first file loses its detail.
I thought the troble could be in the primary key, but it is set just on its id, and the id for new files is set by the oracle sequence.
Why happends an update for Details also if I made a: new DetailsEntity(null,"Test"); ? If i'm not wrong the update must be provided only if I get an object from a select and i change it, not if create a new java entity.

Thank you for your help.

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CDillinger

Post subject: Re: Many to one, one to many

Posted: Mon Dec 07, 2009 5:59 am

Senior

Joined: Tue Oct 28, 2008 10:39 am
Posts: 196

Please post your mappings.

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Tobiascapin

Post subject: Re: Many to one, one to many

Posted: Mon Dec 07, 2009 6:43 am

Newbie

Joined: Mon Dec 07, 2009 5:09 am
Posts: 3

These are the two mappings.

Code:

<hibernate-mapping>
 <class name="entity.FilesEntity" table="FILES">
  <id name="id" type="java.lang.Long">
   <column name="ID" precision="22" scale="0"/>
   <generator class="sequence">
    <param name="sequence">SEQ_FILES</param>
   </generator>
  </id>
  <property generated="never" lazy="false" name="name" type="string">
   <column length="64" name="NAME" not-null="true"/>
  </property>
  <set cascade="all-delete-orphan" inverse="true"  name="details" order-by="ID" sort="unsorted">
   <key>
    <column name="FILE" not-null="true" precision="22" scale="0"/>
   </key>
   <one-to-many class="entity.DetailsEntity"/>
  </set>
 </class>
</hibernate-mapping>

Code:

<hibernate-mapping>
 <class name="entity.DetailsEntity" table="DETAILS">
  <id name="id" type="java.lang.Long">
   <column name="ID" precision="22" scale="0"/>
   <generator class="sequence">
    <param name="sequence">SEQ_DETAILS</param>
   </generator>
  </id>
  <many-to-one
   class="entity.FilesEntity"
   fetch="select" name="FilesEntity" update="false">
   <column name="FILE" not-null="true" precision="22" scale="0"/>
  </many-to-one>
  <property generated="never" lazy="false" name="string" type="string">
   <column length="64" name="STRING"/>
  </property>
 </class>
</hibernate-mapping>

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Tobiascapin

Post subject: Re: Many to one, one to many

Posted: Wed Dec 09, 2009 12:35 pm

Newbie

Joined: Mon Dec 07, 2009 5:09 am
Posts: 3

Can be the "many-to-one" attribute update="false" useful?
Thanks.

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