Hi,

I have a problem when I changed the collection from <bag> to <set>. I have 3 tables, Jobseeker, Application and Job respectively.

Jobseeker table
JobseekerID
Name.............


Application table
ID
JobseekerId
JobID
When

Job
JobID
JobTitle.............

the mapping look like the followings:


<class name="Entity.Jobseeker, Entity" table="Jobseeker ">
<id name="Id" column="JobseekerID" type="int">
<generator class="native" />
</id>
<bag name="AppliedJobs" order-by="`When` Desc" >
<key column="JobseekerId" />
<one-to-many class="Entity.Application, Entity" />
</bag>
</class>

<class name="Entity.Application, Entity" table="Application" lazy="true">
<id name="Id" column="ID" type="int">
<generator class="native" />
</id>
<property name="JobID" column="JobID" type="int" insert="false" />
<property name="JobseekerId" column="JobseekerId" type="int" />
<property name="When" column="`when`" type="DateTime" />

<many-to-one name="AppliedJob" class="Entity.Job, Entity" fetch="join" column="JobID" not-found="ignore" not-null="true" />
</class>

Initially, I used <bag>. It worked just find. The only thing was that my old application created lots of dups. Also, the row remains there in the application table after a job is deleted. Therefore, I switched it to use <set> that helps me dedup all those dups created by my old app. However, nhibernate complains when I try to sort the collection like I did for <map>:

<set name="AppliedJobs" order-by="`When` Desc" >
<key column="JobseekerId" />
<one-to-many class="Entity.Application, Entity" />
</set>


The exception message was "No implementation of generic set". Did I miss something? Can anyone help me with this? Thanks a lot.

Can you post your code ? Sounds like a problem with the type. You have to change the property from IList to ISet, when you switch to set. The ISet stuff comes with Iesi.Collections.

Thank you for your response. I did use ISet for the type.

namespace AfterCollege.Wrapper
{
[Serializable]
public class Jobseeker
{
#region Member Variables

protected int _jobseekerId;
[NonSerialized]
protected ISet<Application> _appliedJobs;

public virtual int JobseekerId
{
get { return this.JobseekerId; }
set { this.JobseekerId= value; }
}

#endregion

[System.Xml.Serialization.XmlIgnore]
public virtual ISet<Application> AppliedJobs
{
get { return _appliedJobs; }
set { _appliedJobs = value; }
}


}

Can you post the stacktrace and the code where you try to retrieve the objects ?

And try generic="true" on the set mapping.

I added generic="true" and I still get the same message. The stacktrace looks like this. I tried to execute the query in my sql console. It seems fine.


- InnerException {"could not initialize a collection: [Entity.Jobseeker.AppliedJobs#268170][SQL: SELECT appliedjob0_.jobseekerid as jobseekerid__2_, appliedjob0_.ID as ID2_, appliedjob0_.ID as ID27_1_, appliedjob0_.jobid as jobid27_1_, appliedjob0_.jobseekerid as jobseekerid27_1_, job1_.jobid as jobid5_0_, job1_.jobtitle as jobtitle5_0_ FROM application appliedjob0_ inner join job job1_ on appliedjob0_.jobid=job1_.recid WHERE appliedjob0_.jobseekerid=? ORDER BY appliedjob0_.`When` Desc]"} NHibernate.ADOException
+ Data {System.Collections.ListDictionaryInternal} System.Collections.IDictionary {System.Collections.ListDictionaryInternal}
HelpLink null string
+ InnerException {"No implementation of generic set with ordering"} System.Exception {System.NotImplementedException}
Message "could not initialize a collection: [Entity.Jobseeker.AppliedJobs#268170][SQL: SELECT appliedjob0_.jobseekerid as jobseekerid__2_, appliedjob0_.ID as ID2_, appliedjob0_.ID as ID27_1_, appliedjob0_.jobid as jobid27_1_, appliedjob0_.jobseekerid as jobseekerid27_1_, job1_.jobid as jobid5_0_, job1_.jobtitle as jobtitle5_0_ FROM application appliedjob0_ inner join job job1_ on appliedjob0_.jobid=job1_.recid WHERE appliedjob0_.jobseekerid=? ORDER BY appliedjob0_.`When` Desc]" string
Source "NHibernate" string
StackTrace " at NHibernate.Loader.Loader.LoadCollection(ISessionImplementor session, Object id, IType type)\r\n at NHibernate.Loader.Collection.CollectionLoader.Initialize(Object id, ISessionImplementor session)\r\n at NHibernate.Persister.Collection.AbstractCollectionPersister.Initialize(Object key, ISessionImplementor session)\r\n at NHibernate.Impl.SessionImpl.InitializeCollection(IPersistentCollection collection, Boolean writing)\r\n at NHibernate.Collection.AbstractPersistentCollection.Initialize(Boolean writing)" string
+ TargetSite {Void LoadCollection(NHibernate.Engine.ISessionImplementor, System.Object, NHibernate.Type.IType)} System.Reflection.MethodBase {System.Reflection.RuntimeMethodInfo}
+ Static members


Stacktrace in InnerException:

+ [System.NotImplementedException] {"No implementation of generic set with ordering"} System.NotImplementedException
+ Data {System.Collections.ListDictionaryInternal} System.Collections.IDictionary {System.Collections.ListDictionaryInternal}
HelpLink null string
+ InnerException null System.Exception
Message "No implementation of generic set with ordering" string
Source "NHibernate" string
StackTrace " at NHibernate.Collection.Generic.PersistentGenericSet`1.BeforeInitialize(ICollectionPersister persister)\r\n at NHibernate.Impl.SessionImpl.GetLoadingCollection(ICollectionPersister persister, Object id, Object resultSetId)\r\n at NHibernate.Loader.Loader.HandleEmptyCollections(Object[] keys, Object resultSetId, ISessionImplementor session)\r\n at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)\r\n at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies)\r\n at NHibernate.Loader.Loader.LoadCollection(ISessionImplementor session, Object id, IType type)" string
+ TargetSite {Void BeforeInitialize(NHibernate.Persister.Collection.ICollectionPersister)} System.Reflection.MethodBase {System.Reflection.RuntimeMethodInfo}

hmmm ....





looks like "order-by" is not supported with a set ... :-( ... I always thought, that order-by is appied to the sql and nothing more ... according to chapter 6.6 of the reference documentation this should work as you implemented it ...

... howeverm I found this http://jira.nhibernate.org/browse/NH-939

I see now. I was wondering why it's not implemented. Anyways, wolli, thank you very much.