Horizontal mapping with inverse-owner doesn't work

Question

Hi,
We encountered a problem of using inverse-owner with horizontal mapping.
Here is the example.
public abstract class A {
//collection of class T
private Set ts = new HashSet()
public class B extends A {
private String name;
public class T {
private A owner;
private String text;
we use metadata factory. package.jdo looks like this.
<class name="T"/>
<class name="A">
<extension vendor-name="kodo" key="jdbc-class-map" value="horizontal"/>
<field name="ts">
<collection element-type="T"/>
<extension vendor-name="kodo" key="inverse-owner"
value="owner"/>
</field>
</class>
<class name="B" persistence-capable-superclass="A">
</class>
mappingtool gives java.lang.ClassCastException
at kodo.jdbc.meta.OneToManyFieldMapping.map(OneToManyFieldMapping.java:126)

Answer 1

Fred-
This is a bug in the automatic generation of mappings. See:
http://bugzilla.solarmetric.com/show_bug.cgi?id=1096
Note this this bug only seems to apply to the automatic generation of
mappings: if you manually compose the .mapping file, then you can
express the one-many mapping (provided you can cast it down to a single
concrete type with the "type" extension).
See the bug report page for an example mapping file solution.
In article <[email protected]>, Fred Chen wrote:
Hi,
When using horizontal mappings, you cannot have an inverse type relation
to a horizontally mapped class (there is no table to hold the
inverse!)But that is precisely why we want to use the inverse mapping (to AVOID the
unecessary middle table). Can you explain in a bit more detail why this is
not supported?
Thanks,
Fred
"Stephen Kim" <[email protected]> wrote in message
news:[email protected]...
When using horizontal mappings, you cannot have an inverse type relation
to a horizontally mapped class (there is no table to hold the
inverse!). However, if you have a concrete type that it is always
mapped to, you can indicate that using the type and element-type
extensions to override the Java declarations to the concrete mapped type.
Fred Chen wrote:
Hi,
We encountered a problem of using inverse-owner with horizontal mapping.
Here is the example.
public abstract class A {
//collection of class T
private Set ts = new HashSet()
public class B extends A {
private String name;
public class T {
private A owner;
private String text;
we use metadata factory. package.jdo looks like this.
<class name="T"/>
<class name="A">
<extension vendor-name="kodo" key="jdbc-class-map" value="horizontal"/>
<field name="ts">
<collection element-type="T"/>
<extension vendor-name="kodo" key="inverse-owner"
value="owner"/>
</field>
</class>
<class name="B" persistence-capable-superclass="A">
</class>
mappingtool gives java.lang.ClassCastException
at
kodo.jdbc.meta.OneToManyFieldMapping.map(OneToManyFieldMapping.java:126)
Steve Kim
[email protected]
SolarMetric Inc.
http://www.solarmetric.com
Marc Prud'hommeaux
SolarMetric Inc.