Re: [castor-user] self-referential and read-only

[Stephen Ince]

Okay. I found my solution. For self-referential relationship I just use null 
and don't use read-only field.
In my case UserScenarioRelation.childUserScenario == null self-referential 
relationship.

<class name="com.opendemand.jdo.UserScenarioRelation" identity="id" 
depends="com.opendemand.jdo.UserScenario" >
<map-to table="user_scenario_relation" />
<cache-type type="none" />
<field name="id" type="integer" required="true" >
<sql name="id" />
</field>
<field name="userScenario" type="com.opendemand.jdo.UserScenario">
<sql name="user_scenario_id" dirty="ignore" />
</field>
<!-- a null value represents a self-referential value -->
<field name="childUserScenario" type="com.opendemand.jdo.UserScenario">
<sql name="child_user_scenario_id" dirty="ignore" />
</field>.
  ----- Original Message ----- 
  From: Stephen Ince 
  To: user@castor.codehaus.org 
  Sent: Wednesday, September 26, 2007 6:46 PM
  Subject: [castor-user] self-referential and read-only


  I am trying to implement a self-referential relationship. I almost having it 
working. 

  Question:
  How do tell castor not todo an update on a column? The column is basically 
for reads and inserts. When I try doing an insert, the read-only column value 
is null and it is not being inserted.

  UserScenario class <-----> UserScenario class. (many-to-many)

  I model it using an intermediate class to contain the relationship, 
UserScenarioRelation.
  UserScenario ---> UserScenarioRelationship.

  The UserScenarioRelationship.childUserScenario and 
UserScenarioRelationship.userScenario are not being set when the field is set 
to 'read-only'.  If don't set read-ony="true" castor will try to recursively 
load (UserScenario) classes in the transaction and subsequently throw a "class 
not loaded in transaction exception"

  Here is my mapping file:

  <class name="com.opendemand.jdo.UserScenario" auto-complete="false" 
identity="userScenarioId" key-generator="MAX">
    <map-to table="user_scenario"/>
    <field name="userScenarioRelations" 
type="com.opendemand.jdo.UserScenarioRelation" collection="arraylist">
      <sql many-key="user_scenario_id" dirty="ignore" />
    </field>

  </class>

  <class name="com.opendemand.jdo.UserScenarioRelation" identity="id" 
depends="com.opendemand.jdo.UserScenario" >
  <map-to table="user_scenario_relation" />
  <cache-type type="none" />
  <field name="id" type="integer" required="true" >
  <sql name="id" />
  </field>
  <!-- these field only get inserted, no updates -->
  <field name="userScenario" type="com.opendemand.jdo.UserScenario">
  <sql name="user_scenario_id" read-only="true" dirty="ignore" />
  </field>
  <!-- these field only get inserted, no updates -->
  <field name="childUserScenario" type="com.opendemand.jdo.UserScenario">
  <sql name="child_user_scenario_id" read-only="true" dirty="ignore" />
  </field>.
     ..
  </class>