Greetings,

I'm trying to retrieve an instance by querying on its abstract base class. The base class doesn't have a table, but each implementing class has a separate one.

I've tried creating the data by hand and programmatically. Creating them programmatically results in entries in the DB, they just don't come out again when queried.

Here's the base class mapping:
<hibernate-mapping>
<class name="UserPreferences">
<id name="id" column="ID_UserPreferences" type="int">
<generator class="identity"/>
</id>
<property name="userId" column="User_ID" type="string"/>
</class>
</hibernate-mapping>

Implementing class mapping:
<hibernate-mapping>
<joined-subclass name="NTIRAInstallUserPrefs"
extends="UserPreferences"
table="UserPreferences" >
<key column="ID_UserPreferences"/>

<property name="decimalPlaces" column="DecimalPlaces" type="int"/>
</joined-subclass>
</hibernate-mapping>

The query "FROM UserPreferences AS up WHERE up.userId = ?"

Thanks.

Hm... Subclass is joined-to-what? :)

I think, you must use <subclass> instead of <joined-subclass>.

Not sure, but doc says "It is perfectly acceptable for the named persistent class to be an interface. You would then declare implementing classes of that interface using the <subclass> element. "

If Your abstract base class is not mapped to a table, then it must not be declared in the Hibernate mapping.
Default table is the unqualified class name (UserPreferences in your case for UserPreferences class).

Remove <class name="UserPreferences"> and map concrete classes with <class ...>

It seems that the mapped class being abstract can only be used with the one table strategy. <joined-subclass> only works with a concrete base class to join off of.

However, I think I found the solution: I should have been using the fully qualified name in the query (I deleted the package names for readability and security, probably should have a place holder instead). That

Hum I think you misunderstood me.

Since your abstract class has no table, Hibernate does not need to / must not have it in it's mapping files.



No <class name="UserPreferences"> in your mapping files.

You can query user preferences by "from my.complete.qualifiedName.UserPreferences". It will return any mapped concrete classes that extends UserPreferences.

"from java.lang.Object" will return the entire database.

Is anyone still watching this issue?