Hi,
I have a table which is a self-referencing table. The parent_id attribute is null if the record has no parent.

I need to get such records with parent_id as null using restrictions\expression creiteria queries.

result = session.createCriteria(Template.class)
.add( Expression.eq("template", null )).list();

but I do not get the desired result.

The parent_id column present in the Database is referencing ID (the primary key) of the same table. The parent_id is null if the record has no parent.

Thanks,
Raj

P.S->
<hibernate-mapping>
<class name="autochecklist.Template" table="template" catalog="comp">
<comment></comment>
<id name="id" type="int">
<column name="id" />
<generator class="assigned" />
</id>
<many-to-one name="options" class="autochecklist.Options" fetch="select">
<column name="optionsId">
<comment></comment>
</column>
</many-to-one>
<many-to-one name="template" class="autochecklist.Template" fetch="select">
<column name="parent_id">
<comment></comment>
</column>
</many-to-one>
<property name="label" type="string">
<column name="label" length="200" not-null="true">
<comment></comment>
</column>
</property>
<property name="type" type="string">
<column name="type" length="45" not-null="true">
<comment></comment>
</column>
</property>
<property name="hidden" type="boolean">
<column name="hidden" not-null="true">
<comment></comment>
</column>
</property>
<set name="templates" inverse="true">
<key>
<column name="parent_id">
<comment></comment>
</column>
</key>
<one-to-many class="autochecklist.Template" />
</set>
</class>
</hibernate-mapping>

Try