Duplicate collection role mapping

arunms · **Posted:** Sun Feb 17, 2008 12:47 pm

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Hibernate version: 1.2.1.4000

Mapping documents:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
namespace="QuickStart" assembly="QuickStart">

<class name="Cat" table="Cat" lazy="false">


<id name="Id" type="Int64" column="CatId" unsaved-value="0">
<generator class="identity"/>
</id>

<property name="Name">
<column name="Name" length="16" not-null="true" />
</property>
<property name="Sex" />
<property name="Weight" />
</class>
</hibernate-mapping>

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
namespace="QuickStart" assembly="QuickStart">
<class name="House" table="House" lazy="false">


<id name="Id" type="Int64" column="HouseID" unsaved-value="0">
<generator class="native"/>
</id>

<property name="LastName">
<column name="LastName" length="16" not-null="true" />
</property>

<bag name="Cats" lazy="false">
<key column="CatID" />
<one-to-many class="Cat" />
</bag>
</class>
</hibernate-mapping>

Code between sessionFactory.openSession() and session.close():

Full stack trace of any exception that occurs:
[DuplicateMappingException: Duplicate collection role mapping QuickStart.House.Cats]
NHibernate.Cfg.Mappings.AddCollection(Collection collection) +111
NHibernate.Cfg.HbmBinder.PropertiesFromXML(XmlNode node, PersistentClass model, Mappings mappings) +235
NHibernate.Cfg.HbmBinder.BindRootClass(XmlNode node, RootClass model, Mappings mappings) +2404
NHibernate.Cfg.HbmBinder.BindRoot(XmlDocument doc, Mappings mappings) +390
NHibernate.Cfg.Configuration.AddValidatedDocument(NamedXmlDocument doc) +64

[MappingException: Could not compile the mapping document: QuickStart.House.hbm.xml]
NHibernate.Cfg.Configuration.LogAndThrow(MappingException me) +38
NHibernate.Cfg.Configuration.AddValidatedDocument(NamedXmlDocument doc) +150
NHibernate.Cfg.Configuration.ProcessMappingsQueue() +12
NHibernate.Cfg.Configuration.AddInputStream(Stream xmlInputStream, String name) +169
NHibernate.Cfg.Configuration.AddResource(String path, Assembly assembly) +177
NHibernate.Cfg.Configuration.AddAssembly(Assembly assembly) +97
QuickStart.NHibernateHelper..cctor() in C:\Workspace\QuickStart\QuickStart\Default.aspx.cs:87

[TypeInitializationException: The type initializer for 'QuickStart.NHibernateHelper' threw an exception.]
QuickStart.NHibernateHelper.GetCurrentSession() in C:\Workspace\QuickStart\QuickStart\Default.aspx.cs:103
QuickStart._Default.Page_Load(Object sender, EventArgs e) in C:\Workspace\QuickStart\QuickStart\Default.aspx.cs:23
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +15
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +34
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +47
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1061

Name and version of the database you are using: SQL Server 2005 express (named instance)

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:

Problems with Session and transaction handling?

Read this: http://hibernate.org/42.html

I'm very new to NHibernate. Please help me. I'm trying to get the QuickStart sample up and running with minor changes. I have a table House which shares a 1 to many relationship with the table Cat. I have two mapping files one for Cat and one for House, which I've attached with this message. I'm not able to get past this issue. Please help.

FlukeFan · **Posted:** Sun Feb 17, 2008 2:53 pm

Hi,

I'm not sure if this is the problem or not, but where you have:

Code:

<bag name="Cats" lazy="false"> 
    <key column="CatID" /> 
    <one-to-many class="Cat" /> 
</bag> 

I would've expected:

Code:

<bag name="Cats" lazy="false"> 
    <key column="HouseID" /> 
    <one-to-many class="Cat" /> 
</bag> 

That is, it is the HouseID column from the Cats table that defines the collection of Cats for a given House. (I'm am assuming, of course, that your Cats table has a HouseID column in it.)

Regards,
Richard

arunms · **Posted:** Sun Feb 17, 2008 4:48 pm

Thanks, Richard for your comment. I changed the mapping files as follows:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
namespace="QuickStart" assembly="QuickStart">

<class name="Cat" table="Cat" lazy="false">


<id name="Id" type="Int64" column="CatId" unsaved-value="0">
<generator class="identity"/>
</id>

<property name="Name">
<column name="Name" length="16" not-null="true" />
</property>
<property name="Sex" />
<property name="Weight" />
<many-to-one name="House" class="House" column="HouseID" />
</class>
</hibernate-mapping>

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
namespace="QuickStart" assembly="QuickStart">
<class name="House" table="House" lazy="false">


<id name="Id" type="Int64" column="HouseID" unsaved-value="0">
<generator class="native"/>
</id>

<property name="LastName">
<column name="LastName" length="16" not-null="true" />
</property>
<bag name="Cats" lazy="false">
<key column="HouseID" />
<one-to-many class="Cat" />
</bag>
</class>
</hibernate-mapping>

Unfortunately, I'm still getting the same error. Any help is greatly appreciated.

FlukeFan · **Posted:** Sun Feb 17, 2008 5:31 pm

Is it possible that the Assembly is being added twice?

e.g., you have both a call to .AddAssembly("AssemblyName") in your startup code, and a line in your config file '<mapping assembly="AssemblyName" />'. Only one of these would be required.

Richard

arunms · **Posted:** Mon Feb 18, 2008 5:55 pm

Thanks, Richard. You were right. I had multiple declarations of the assembly. I've not quiet figured it out, yet, but when I removed the reference to Cat from my SessionFactory code, it started working.