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arnaud.java

Post subject: Parent/child

Posted: Wed Aug 04, 2004 5:23 am

Newbie

Joined: Fri Jul 23, 2004 4:49 am
Posts: 7
Location: France

Hello,

I'm using hibernate 2.1.4

What I would like to do is the same thing that the parent/child example in the hibernate documentation except the primary key is the id column and the parent_id (which is the foreign key).

So it makes possible to have :

Code:

  id   |   parent_id
---------------------
  0    |    1
  1    |    1
  0    |    2
  1    |    2
...

The hibernate example :
http://www.hibernate.org/hib_docs/reference/en/html/collections.html#collections-example

Is anybody can help me?
Thx.

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arnaud.java

Post subject: Re: Parent/child

Posted: Wed Aug 04, 2004 5:27 am

Newbie

Joined: Fri Jul 23, 2004 4:49 am
Posts: 7
Location: France

Hello,

I'm using hibernate 2.1.4

What I would like to do is the same thing that the parent/child example in the hibernate documentation except the primary key of the child table is the id column and the parent_id (which is the foreign key).

So it makes possible to have :

Code:

  id   |   parent_id
---------------------
  0    |    1
  1    |    1
  0    |    2
  1    |    2
...

The hibernate example :
http://www.hibernate.org/hib_docs/reference/en/html/collections.html#collections-example

Is anybody can help me?
Thx.

Top

steve

Post subject:

Posted: Wed Aug 04, 2004 12:15 pm

Hibernate Team

Joined: Tue Aug 26, 2003 3:00 pm
Posts: 1816
Location: Austin, TX

Code:

    <class name="my.Entity">
        <id name="id">
            <generator class="sequence"/>
        </id>
        <many-to-one name="parent" column="parent_id" class="my.Entity"/>
        <set name="children" lazy="true">
            <key column="parent_id"/>
            <one-to-many class="my.Entity"/>
        </set>
    </class>

No different really than the example you list.

BTW, the forum does have a search. This has been asked and discussed many times before.

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arnaud.java

Post subject:

Posted: Wed Aug 04, 2004 3:18 pm

Newbie

Joined: Fri Jul 23, 2004 4:49 am
Posts: 7
Location: France

Thank you for replying Steve.

However I am a new hibernate user and I don't understand the <many-to-one... in your sample. It seems like the my.Entity object have a parent method?

If it was already posted could you give me the link, cause I didn't find it.

I just want to add the parent_id column in the primary key of the child table. Below the code which inspired my code. I try many things but it doesn't work. In this code the PK contains only the id column in the child table.

Code:

<hibernate-mapping>
    <class name="eg.Parent">
        <id name="id">
            <generator class="sequence"/>
        </id>
        <set name="children" inverse="true" lazy="true">
            <key column="parent_id"/>
            <one-to-many class="eg.Child"/>
        </set>
    </class>

    <class name="eg.Child">
        <id name="id">
            <generator class="sequence"/>
        </id>
        <property name="name"/>
        <many-to-one name="parent" class="eg.Parent" column="parent_id" not-null="true"/>
    </class>
</hibernate-mapping>

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steve

Post subject:

Posted: Wed Aug 04, 2004 4:32 pm

Hibernate Team

Joined: Tue Aug 26, 2003 3:00 pm
Posts: 1816
Location: Austin, TX

Oh, missed the composite key bit. Check out http://www.hibernate.org/hib_docs/reference/en/html/components.html#components-compositeid

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