Is it possible to query a map without a join on the parent?

fdurden · **Joined:** Thu Nov 17, 2005 1:44 pm **Posts:** 6

Hibernate version:
3.0.5

Hello,

So I have the following mapping file and what I'd like to do is build a query to get some of the indexes and elements from the attributeValues Map, based on the ID (key) and ATTRIBUTE_NAME (index) columns of the ATTRIBUTE_VALUES table, all this without a join on the ENT_SPEC_VAL table:

Code:

   <class 
      name="eg.EntitySpecificationValueImpl"
      table="ENT_SPEC_VAL"
      discriminator-value="ENT_SPEC">
      
      <id name="identifier" type="long" unsaved-value="0" column="ID">
         <generator class="native"/>
      </id>
      <discriminator column="DISCR" type="string"/>
      
      <map name="attributeValues" lazy="true" table="ATTRIBUTE_VALUES" access="field">
         <key column="ID"/>
         <index column="ATTRIBUTE_NAME" type="string"/>
         <element type="eg.GenericAttributeType" not-null="true">
            <column name="VALUE"/>
         </element>
      </map>
      <subclass name="eg.ServiceSpecificationValueImpl" discriminator-value="SERV_SPEC">
      </subclass>
   </class>

I've managed to write the following HQL query that returns a list of Object[] that have the index and element values (the key and value of the Map), but this has a join between the two tables that is not (really) necessary.

Code:

select index(attribs), elements(attribs) 
from eg.EntitySpecificationValue esv 
join esv.attributeValues attribs 
where index(attribs) in (:atVals) and esv.identifier = :id

Is there a way to do this without using a join? I would need to be able to refer to the ATTRIBUTE_VALUES.ID column in HQL, which does not seem to be possible.

So my aim is to have Hibernate generate SQL that looks like

Code:

SELECT av.attribute_name, av.value
FROM attribute_values av 
WHERE av.id = ? AND av.attribute_name IN (?)