in db.DBAttribute you declare two PK fields, thus in collection-descriptor of db.DBObject you have to declare both fields as inverse-foreignkey to match correctly.
I don't know if there is an additional side-effect when declaring PK/reference fields (e.g. 'owner') anonymous.
As I said in previous mails, I don't recommend to use anonymous fields beyond 1:1 references.
regards, Armin
Alessandro Villamaina wrote:
Hi all,
I have a problem using the auto-delete optiion in conjunction with anonymous fields.
The classes I have to be made persistent in the DB (I'm using PostgreSQL) are (pseudo code):
class DBObject private String name private Collection attributes
class DBAttribute private String name private String value
I want to set things up in order to get the DBAttributes belonging to a DBObject deleted when the DBObject itself gets deleted.
The repository_user.xml file looks like
<class-descriptor class="db.DBObject" table="DBOBJECT">
<field-descriptor
name="name"
column="NAME"
jdbc-type="VARCHAR"
primarykey="true"
/>
<collection-descriptor
name="_attributes"
auto-delete="true"
auto-update="true"
element-class-ref = "db.DBAttribute">
<inverse-foreignkey field-ref = "owner" />
</collection-descriptor> </class-descriptor>
<class-descriptor
class="db.DBAttribute"
table="DBATTRIBUTE">
<field-descriptor
name="name"
column="NAME"
primarykey="true"
jdbc-type="VARCHAR"
/>
<field-descriptor
name="value"
column="VALUE"
jdbc-type="VARCHAR"
/>
<field-descriptor
name="owner"
column="OWNER"
jdbc-type="VARCHAR"
primarykey="true"
access="anonymous"
/>
</class-descriptor>
As you can see, the OWNER column in the DBATTRIBUTE table keeps the link between an object and its attributes. There is no such attribute in the DBAttribute class, so I decided to make it an "anonymous" field, letting OJB handle it for me.
The primary key of a DBATTRIBUTE record is the couple <name, owner>, since I want to allow a single attribute name for each object.
When I save the DBObjects, everything works fine, and DBAttributes are made persistent along with their DBObjects. Peering into the DB tables, I can check that, for each record, the OWNER column contains the right reference to the owner object, and that is OK.
When I delete one of the DBObjects, its attributes are NOT deleted.
I tried to set the log4j logging level to DEBUG, and it turned out that the DELETE sql statements where, for each of the DBATTRIBUTE to be deleted:
DELETE FROM DBATTRIBUTE WHERE name="name1" AND owner = NULL
Obviously nothing is deleted from DBATTRIBUTE, since no owner is null in the table. The funny thing is that such DELETE statements are generated ONLY for the attributes that should be deleted, not for all attributes. This means that OJB "knows" (looking at the owner field, I guess) which attributes belong to the DBOBJECT and have to be deleted, but fails in assigning the right value to owner in the DELETE statement.
Does anyone know how to solve this? Is this a bug or am I doing something wrong?
Thanks a lot!
Alessandro
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