i have an abstract class that has 4 subclasses here is the xml below

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="TProDataTransferObjects" assembly="TProDataTransferObjects" auto-import="true">
<class name="ProjectActivity" abstract="true" table="PROJECT_ACTIVITY" lazy="false">
<id name="ProjectID" column="PROJ_ID">
<generator class="assigned"/>
</id>
<discriminator column="ACTIVITY_ID" type="string" />
<property column="ACTIVITY_ID" name="ActivityID"></property>
<property column="last_dml_dttm" name="LastUpdateDate"></property>

<subclass name="CST" discriminator-value="CST">
<join table="PROJECT_CST">
<key column="PROJ_ID"/>
<property name="dmlUser" column="LAST_DML_USER"/>
</join>
</subclass>


<subclass name="PE" discriminator-value="PE">
<join table="PROJECT_PE">
<key column="PROJ_ID"/>
<property name="dmlUser" column="LAST_DML_USER"/>
</join>
</subclass>


<subclass name="ROW" discriminator-value="ROW">
<join table="PROJECT_ROW">
<key column="PROJ_ID"/>
<property name="dmlUser" column="LAST_DML_USER"/>
</join>
</subclass>


<subclass name="UTIL" discriminator-value="UTL">
<join table="PROJECT_UTL">
<key column="PROJ_ID"/>
<property name="dmlUser" column="LAST_DML_USER"/>
</join>
</subclass>

</class>
</hibernate-mapping>


here is the code behind

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Runtime.Serialization;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;

namespace TProDataTransferObjects
{
[Serializable]
[DataContract(Namespace = "TProDataTransferObjects")]
public abstract class ProjectActivity
{
[DataMember]
public virtual string ProjectID { get; set; }

[DataMember]
public virtual string ActivityID { get; set; }

[DataMember]
public virtual string LastUpdateDate { get; set; }

}

[Serializable]
[DataContract(Namespace = "TProDataTransferObjects")]
public class CST : ProjectActivity
{
[DataMember]
public virtual string dmlUser { get; set; }
}


[Serializable]
[DataContract(Namespace = "TProDataTransferObjects")]
public class PE : ProjectActivity
{
[DataMember]
public virtual string dmlUser { get; set; }
}


[Serializable]
[DataContract(Namespace = "TProDataTransferObjects")]
public class ROW : ProjectActivity
{
[DataMember]
public virtual string dmlUser { get; set; }
}


[Serializable]
[DataContract(Namespace = "TProDataTransferObjects")]
public class UTIL : ProjectActivity
{
[DataMember]
public virtual string dmlUser { get; set; }
}

}



when i run this below

[OperationContract]
public IList<ProjectExts> ViewCurrentProjects(string ProjectID)
{
using (ISession session = NHibernateContext.Current().Session)
{
IQuery query;
var sql = "from ProjectExts a " +
" inner join fetch a.Activities c " +
" inner join fetch a.NewProjectTable b " +
" inner join fetch a.UserTable d " +
" where a.ProjectID =:ProjectID " +
" and c.LastUpdateDate =(select max(LastUpdateDate) from a.Activities " +
" where a.ProjectID =:ProjectID)";


query = session.CreateQuery(sql)
.SetParameter("ProjectID", ProjectID);
IList<ProjectExts> project = query.List<ProjectExts>();

return project;

}

}

the funny behaviar is that it loops 4 times but the data is loaded into project, but no object returns.. i still do not know why is it looping 4 times.. project is populated fine with all classes and according to activity id i get the right record back from database but it is looping 4 times and every time project is populated... but still no xml returns...i have been trying to figure this our for 4 days now and i am new to nhibernate.... thanks

here is project ext class

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="TProDataTransferObjects" assembly="TProDataTransferObjects" auto-import="true">
<class name="ProjectExts" table="project_exts" lazy="false">
<id name="ProjectID" column="proj_id" type="string">
<generator class="assigned"/>
</id>

<property column="manager_empid" name="ManagerEmpId"></property>
<property column="cons_status_code" name="ConsStatCode"></property>
<one-to-one class="NewProjects" name="NewProjectTable"></one-to-one>
<one-to-one class="Users" name="UserTable" foreign-key="ManagerEmpId" ></one-to-one>

<set name="Activities" lazy="true">
<key column="proj_id" />
<one-to-many class="ProjectActivity"/>
</set>

</class>
</hibernate-mapping>

this is mapped to project activity, the one that is an abstract class..


using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Runtime.Serialization;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.Collections;



namespace TProDataTransferObjects
{
[Serializable]
[DataContract(Namespace = "TProDataTransferObjects")]
public class ProjectExts
{
[DataMember]
public string ProjectID { get; set; }

[DataMember]
public string ManagerEmpId { get; set; }

[DataMember]
public string ConsStatCode { get; set; }

[DataMember]
public NewProjects NewProjectTable { get; set; }

[DataMember]
public Users UserTable { get; set; }

[DataMember]
public ICollection<ProjectActivity> Activities { get; set; }

}}

You must also define KnownType.
See sample:http://codeplex.com/NHibernateWCF

do i have to? it is working without it.

can not return type distinct from ProjectExts, if you do not define KnownType.

ok thanks, where do i need to define the known type? give me an example please...

section Web.config from this example:http://nhibernatewcf.codeplex.com

actually i added it to the base class before defining and it worked. thanks a bunch

[DataContract(Namespace = "TProDataTransferObjects")]
-here is what i added knowntype....
public abstract class ProjectActivity