Sylvain,
Something like this?
<class-descriptor
class="A"
table="A"
>
<field-descriptor id="1"
name="A_id"
column="A_ID_PK"
jdbc-type="INTEGER"
primarykey="true"
autoincrement="true"
/>
<field-descriptor id="2"
name="name"
column="NAME"
jdbc-type="VARCHAR"
/>
<reference-descriptor
name="qualifiedARef"
class-ref="QualifiedARef"
>
<foreignkey field-id-ref="4"/>
</reference-descriptor>
</class-descriptor>
<class-descriptor
class="QualifiedARef"
table="QualifiedARef"
>
<field-descriptor id="1"
name="qualifiedId"
column="QUALIFIEDAREF_PK"
jdbc-type="INTEGER"
primarykey="true"
autoincrement="true"
/>
<field-descriptor id="2"
name="A_id"
column="A_ID_FK"
jdbc-type="INTEGER"
/>
<field-descriptor id="3"
name="relationInfo"
column="RELATION_INFO"
jdbc-type="VARCHAR"
/>
<reference-descriptor
name="classARef"
class-ref="A"
>
<foreignkey field-id-ref="2"/>
</reference-descriptor>
</class-descriptor>
Phil
[EMAIL PROTECTED] wrote:
Phil,
Ok but how do you do the self-reference?
Sorry I don't understand.
Sylvain
-----Message d'origine-----
De: Phil Warrick [mailto:[EMAIL PROTECTED]]
Date: lundi, 16. d�cembre 2002 16:43
�: OJB Users List
Objet: Re: OJB and recursive relationship
Sylvain,
Only one A fk is required in the QualifiedARef table:
QualifiedARef
-------------
int qualifiedARef_PK
String relationInfo
int A_id_FK
Phil
>
[EMAIL PROTECTED] wrote:
So, more in practise:
Classes:
Class A { Classe QualifiedARef {
int A_id int qualifiedId
String name A classARef
QualifiedARef qualifiedARef String relationInfo
... int A_id
} ....
}
Relationnal tables:
A QualifiedARef
- -------------
int A_id_PK int qualifiedARef_PK
String name int A_id_class_ref_FK
String relationInfo
int A_id_FK
Am I on the right way?
is there a probem in the QualifiedARef table because there are 2 FK for A??
Thank you
Regards
Sylvain
-----Message d'origine-----
De: Phil Warrick [mailto:[EMAIL PROTECTED]]
Date: lundi, 16. d�cembre 2002 15:59
�: OJB Users List
Objet: Re: OJB and recursive relationship
Hi Sylvain,
Yes, then class A instead has a reference to a class QualifiedARef (or a
collection of these). QualifiedARef holds the relation info and a
reference to the target A. If bidirectionality is important, it can
hold a reference to both of the As in the relation.
Phil
[EMAIL PROTECTED] wrote:
Hi Phil,
Thank you for your answer.
Is it also possible if you qualified this self reference (add information about relation)?
For example if class A have a reference to another instance of class A and this reference has information like reference_name or something like that.
Regards
Sylvain
-----Message d'origine-----
De: Phil Warrick [mailto:[EMAIL PROTECTED]]
Date: lundi, 16. d�cembre 2002 15:14
�: OJB Users List
Objet: Re: OJB and recursive relationship
Hi Sylvain,
OJB handles self references fine. In other words class A can have a
reference to another instance of class A or a collection of class As.
You may need to make these proxies if the graph is very large and you
need to control the hits to the db.
Phil
[EMAIL PROTECTED] wrote:
Hello,
I have a situation with recursive relationship:
I have a class Software that represents the softwares that could be installed on my machine. Some of these softwares must have other softwares installed before to be able to be installed.
So, I have a recurvive relationship here.
How do you implement this relationship with OJB?
Thank you
Sylvain
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