Cascading issue when deleting an object in a one-to-one relationship using Fluent NHibernate

Question

I have the following db tables which I have simplified for this example:

Webpage Id, URLIdentifier

WebpageMetaData strong> Webpage Keywords

Webpage_id is the main key for the table, and the foriegn key is for the table of the web page.

Then I use Fluent NHibernate and its auto-tuning function to map them to the following POCO classes:

public class Webpage
{
    public virtual int Id { get; set; }
    public virtual string UrlIdentifier { get; set; }
    public virtual WebpageMetaData WebpageMetaData { get; set; }

}

public class WebpageMetaData
{
    public virtual int Id { get; set; }
    public virtual string Keywords{ get; set; }
    public virtual Webpage Webpage { get; set; }

}

I want to map these objects as one-to-one, so I redefine automation as follows:

public class WebpageMap : IAutoMappingOverride<Webpage>
{        
    public void Override(AutoMapping<Webpage> mapping)
    {
        mapping.HasOne(w => w.WebpageMetaData)
            .Not.Constrained()
            .Fetch.Join()
            .Cascade.All();
    }
}

public class WebpageMetaDataMap : IAutoMappingOverride<WebpageMetaData>
{
    public void Override(AutoMapping<WebpageMetaData> mapping)
    {
        mapping.Id(w => w.Id, "Webpage_id").GeneratedBy.Foreign("Webpage");

        mapping.HasOne(w => w.Webpage)
            .ForeignKey("Webpage_id")
            .Constrained()
            .Fetch.Join()
            .Cascade.None();
    }
}

I tested these mappings and cascading rules, and they work to select, insert, and update. However, when I perform the removal of WebpageMetaData, I get an exception saying that

" cascade ( ) [WebpageMetaData # 524]"

- :

webpageMetaData.Webpage.WebpageMetaData = null;

, ??! ? ?

.

1: NH-, FLuent, , NHibernator:)

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-access="property" auto-import="true" default-cascade="none" default-lazy="true">
  <class xmlns="urn:nhibernate-mapping-2.2" name="EveryPage.Core.Domain.Webpage, EveryPage.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" table="`Webpage`">
    <id name="Id" type="System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" unsaved-value="0">
      <column name="Id" />
      <generator class="identity" />
    </id>
    <one-to-one cascade="all" class="EveryPage.Core.Domain.WebpageMetaData, EveryPage.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" constrained="false" fetch="join" name="WebpageMetaData" />
    <property name="UrlIdentifier" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="UrlIdentifier" />
    </property>    
  </class>
</hibernate-mapping>


<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-access="property" auto-import="true" default-cascade="none" default-lazy="true">
  <class xmlns="urn:nhibernate-mapping-2.2" name="EveryPage.Core.Domain.WebpageMetaData, EveryPage.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" table="`WebpageMetaData`">
    <id name="Id" type="System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" unsaved-value="0">
      <column name="Webpage_id" />
      <generator class="foreign">
        <param name="property">Webpage</param>
      </generator>
    </id>
    <one-to-one cascade="none" class="EveryPage.Core.Domain.Webpage, EveryPage.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" constrained="true" fetch="join" foreign-key="Webpage_id" name="Webpage" />
    <property name="Keywords" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Keywords" />
    </property>
  </class>
</hibernate-mapping>

Answer 1

, . NH, - - - ( = ) , . ( "--" , PK)

, , , .

Answer 2

Hm, Cascade-all-delete-orphan ?