I have three tables, one of which is a relationship table between the other two. For simplicity sake, here are the relevant tables/columns (I did not design these tables or their naming, don't yell at me lol):

table: povendsite
column: vendno
column: vend_site

table: rt_sub_category
column: category
column: sub_category

table: store_services_vend_subcat
column: vendno
column: vend_site
column: category
column: sub_category

the first two tables above are two tables that have rleationships stored in the third table. I have three objects for these tables, mappings are as follows (relevant parts):

<class name="VendorSite" table="povendsite">
<composite-id name ="id" class="VendorSiteKey">
<key-many-to-one name="vendor" column="vendNo" class="Vendor" lazy="false"/>
<key-property name="siteNo" column="site_no"/>
</composite-id>

<class name="SubCategory" table="rt_sub_category">
<composite-id name ="id" class="SubCategoryKey">
<key-property name="subCategory" column="sub_category" />
<key-property name="category" column="category" />
</composite-id>

<class name="VendorSubCategoryRelationship" table="vendor_subcateories">
<composite-id name ="id" class="VendorSubCategoryRelationshipKey">
<key-many-to-one name="vendorSite" column="site_No" class="VendorSite" lazy="false">
<column name="vendno"/>
<column name="site_no"/>
</key-many-to-one>
<key-many-to-one name="subCategory" class="SubCategory" lazy="false">
<column name="sub_category" />
<column name="category"/>
</key-many-to-one>
</composite-id>


All this being said, I need a named query (I think this is the best way to go here) where I will be given a subcategory and I need to find all of the vendor sites (combination of vendno and vend_site) that do not currently have a relationship with that category/subcategory combination. I have no idea how to start writing this named query...any ideas?

oh I forgot to mention, I am using Java 1.4 and hibernate 3 :)