Hibernate version:
1.2.0-GA
Mapping documents:
<?xml version="1.0"?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="ML.SMI.MDS.BusinessObjects" schema="Trades" namespace="ML.SMI.MDS.BusinessObjects">
<class
name="TradeExternalMap"
table="t_trade_external_map"
>
<id
name="Id"
type="Int32"
column="id"
>
<generator class="native"/>
</id>

<property
name="ExternalId"
column="external_id"
type="String"
not-null="false"
length="50"
/>
<many-to-one
name="TradeFeed"
column="feed_id"
class="TradeFeed"
not-null="false"
/>
<many-to-one
name="TradeType"
column="trade_type_id"
class="TradeType"
not-null="false"
fetch="join"
not-found="ignore"
unique="true"
lazy="false"
/>
<many-to-one
name="ProductType"
column="product_type"
class="ProductType"
not-null="false"
fetch="join"
not-found="ignore"
unique="true"
lazy="false"
/>

<join table="link_result_trade_externalmap" optional="true" inverse="true">
<key column="trade_id"/>
<many-to-one
name="MarginResult"
column="result_id"
class="MarginResult"
not-null="false"
cascade="save-update"
lazy="true"
/>
</join>
</class>
</hibernate-mapping>

Full stack trace of any exception that occurs:
2007-09-14 15:23:29,798 [TestRunnerThread]ERROR NHibernate.Cfg.Configuration [HibernateSessionFactory()] &lt;(null)&gt; - ML.SMI.MDS.DatabaseAdapters.HibernateMappingFiles.TradeExternalMap.hbm.xml(48,4): XML validation error: The element 'class' in namespace 'urn:nhibernate-mapping-2.2' has invalid child element 'join' in namespace 'urn:nhibernate-mapping-2.2'. List of possible elements expected: 'urn:nhibernate-mapping-2.2:property urn:nhibernate-mapping-2.2:many-to-one urn:nhibernate-mapping-2.2:one-to-one urn:nhibernate-mapping-2.2:component urn:nhibernate-mapping-2.2:dynamic-component urn:nhibernate-mapping-2.2:any urn:nhibernate-mapping-2.2:map urn:nhibernate-mapping-2.2:set urn:nhibernate-mapping-2.2:list urn:nhibernate-mapping-2.2:bag urn:nhibernate-mapping-2.2:idbag urn:nhibernate-mapping-2.2:array urn:nhibernate-mapping-2.2:primitive-array urn:nhibernate-mapping-2.2:subclass urn:nhibernate-mapping-2.2:joined-subclass urn:nhibernate-mapping-2.2:loader urn:nhibernate-mapping-2.2:sql-insert urn:nhibernate-mapping-2.2:sql-update urn:nhibernate-mapping-2.2:sql-delete urn:nhibernate-mapping-2.2:filter'.
NHibernate.MappingException: ML.SMI.MDS.DatabaseAdapters.HibernateMappingFiles.TradeExternalMap.hbm.xml(48,4): XML validation error: The element 'class' in namespace 'urn:nhibernate-mapping-2.2' has invalid child element 'join' in namespace 'urn:nhibernate-mapping-2.2'. List of possible elements expected: 'urn:nhibernate-mapping-2.2:property urn:nhibernate-mapping-2.2:many-to-one urn:nhibernate-mapping-2.2:one-to-one urn:nhibernate-mapping-2.2:component urn:nhibernate-mapping-2.2:dynamic-component urn:nhibernate-mapping-2.2:any urn:nhibernate-mapping-2.2:map urn:nhibernate-mapping-2.2:set urn:nhibernate-mapping-2.2:list urn:nhibernate-mapping-2.2:bag urn:nhibernate-mapping-2.2:idbag urn:nhibernate-mapping-2.2:array urn:nhibernate-mapping-2.2:primitive-array urn:nhibernate-mapping-2.2:subclass urn:nhibernate-mapping-2.2:joined-subclass urn:nhibernate-mapping-2.2:loader urn:nhibernate-mapping-2.2:sql-insert urn:nhibernate-mapping-2.2:sql-update urn:nhibernate-mapping-2.2:sql-delete urn:nhibernate-mapping-2.2:filter'. ---> System.Xml.Schema.XmlSchemaValidationException: The element 'class' in namespace 'urn:nhibernate-mapping-2.2' has invalid child element 'join' in namespace 'urn:nhibernate-mapping-2.2'. List of possible elements expected: 'urn:nhibernate-mapping-2.2:property urn:nhibernate-mapping-2.2:many-to-one urn:nhibernate-mapping-2.2:one-to-one urn:nhibernate-mapping-2.2:component urn:nhibernate-mapping-2.2:dynamic-component urn:nhibernate-mapping-2.2:any urn:nhibernate-mapping-2.2:map urn:nhibernate-mapping-2.2:set urn:nhibernate-mapping-2.2:list urn:nhibernate-mapping-2.2:bag urn:nhibernate-mapping-2.2:idbag urn:nhibernate-mapping-2.2:array urn:nhibernate-mapping-2.2:primitive-array urn:nhibernate-mapping-2.2:subclass urn:nhibernate-mapping-2.2:joined-subclass urn:nhibernate-mapping-2.2:loader urn:nhibernate-mapping-2.2:sql-insert urn:nhibernate-mapping-2.2:sql-update urn:nhibernate-mapping-2.2:sql-delete urn:nhibernate-mapping-2.2:filter'.
--- End of inner exception stack trace ---

Name and version of the database you are using:
SQL Server 2005


As you can see the mapping file seems to me ok but then I get that error. I have looked at the docs and I think everything is in order unless I am pointing to some incorrect namespace or something. Anyone any ideas.
Thanks.

I believe the <join table> element is not available for for NHibernate. I did read about a patch you can apply, NH-466, but have never used it.
See http://jira.nhibernate.org/browse/NH-466

I've never tried to use <join table> but have seen a blog about it:
http://andersnoras.com/blogs/anoras/arc ... ables.aspx

The blog said the it wouldn't make it into the final 1.2 build...not sure what current disposition is. You could try getting code off the trunk and see if it's supported there.

However, you could use a <subclass_join>. It looks like this and is under <class>


Your class structure would have <class> as your base and would be something like class AbstractTradeExternalMap. TradeExternalMap would derive from that and properties pertaining to the derived class would go into the joined-subclass section.

Problems with this?
1. "key" of joined-subclass is the foreign key to the parent table...this
doesn't look to fit into your domain model.
2. subclass and joined-subclass can't be used together in the same class
mapping.

Alternatively, you can have a TradeExternalMapResult class and set up a one-to-one relationship with TradeExternalMap. You'd declare the one-to-one so that it's sharing the primary key with TradeExternalMap.

Does that help?

The <join> element is implemented in the trunk, but it is not included in 1.2GA. It is slated to be included in 2.0.

Thanks Guys,

This was very helpful. jlockwood, thanks for youre suggestions.

NP, anytime.

Hi JLockwood,

Just a quick question. In the case of the one-to-one mapping with the shared primary key, how would I do this using the link table TradeExternalMapResult.

TradeExternalMap --> TradeExternalMapResult --> MarginResult.

I am not sure that this is possible using the link table is it !

thanks,
Richie.

I think you would have to have a class that represents the association table, then it wouldn't be a problem. I'm not sure, off hand, if it's possible without the additional class. (If you can make it work drop a line and tell me how...I'll add it to my tool bag)

Hold that thought, I think chapter 19 may have what you are looking for:
http://www.hibernate.org/hib_docs/nhibe ... pings.html

Author class is associated to Work class through the author_work table. The example given is bi-directional. Just check out the page and search for 'author_work". Think it will do it for you.

Yeah, I was thining the same. I reckon I will see if I can integrate that patch first and when I do I will create a new post on it. If that fails then I may have to go with either a many to many solution of some kind. I dont want to expose the link table if possible. It would be a hack essentailly that I would have to change later on down the line me thinks.

thanks again,
Richie.

<replying to the many-to-many solution>

Again, exactly what I reckon I will have to do. Its probably the easiest way right now in order to get around this. I have another post up asking if anyone has integrated with the NH-466 patch and I will see how I get along with that first.

Ta.
Richie.