<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
  <class name="XXX.Art, XXX" table="Art">
    <id name="Id" column="BuzzUserArtID" type="guid">
      <generator class="guid.comb"/>
    </id>

    <many-to-one name="Owner" class="XXX.Artist, XXX"
column="BuzzUserID" not-null="true" />
    <many-to-one name="Category" class="XXX.XXXCategory, XXX"
column="XXXCategoryID" />

    <property name="Title" type="String" length="50" column="Title" />
    <property name="Description" type="String" length="4000"
column="Description" />
    <property name="Width" type="integer" column="Width" />
    <property name="Height" type="integer" column="Height" />
    <property name="ArtDate" type="Date" column="BuzzUserArtDate" />
    <property name="DateCreated" type="Date" column="DateCreated"
insert="false" update="false" />
    <property name="DateModified" type="Date" column="DateModified"
insert="false" />
    <property name="BuzzCount" type="integer" column="BuzzCount" />
    <property name="Rating" type="double" column="Rating" />
    <property name="Url" type="String" column="URL" />
    <property name="UrlResized" type="String" column="URLResized" />
    <property name="UrlThumbnail" type="String" column="URLThumbnail" /

    <property name="IsProcessed" type="Boolean" column="IsProcessed" /

    <property name="Scrapped" type="Boolean" column="Scrapped"
insert="false" />

    <bag  name="Comments" inverse="true" cascade="all-delete-orphan"
lazy="true">
      <key column="BuzzUserArtID" on-delete="cascade"/>
      <one-to-many class="XXX.BuzzUserArtComment, XXX" />
    </bag>

  </class>
</hibernate-mapping>

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
  <class name="XXX.BuzzUser, XXX" table="BuzzUser" lazy="true">
    <id name="Id" column="BuzzUserID" type="guid">
      <generator class="guid.comb"/>
    </id>

    <property name="FirstName" type="String" length="50"
column="FirstName"  not-null="true" />
    <property name="LastName" type="String" length="100"
column="LastName" not-null="true" />
    <property name="FullName" type="String" length="150"
column="FullName" insert="false" update="false" />
    <property name="Email" type="String" length="50" column="Email"
not-null="true" />
    <property name="UserName" type="String" length="50"
column="UserName" not-null="true" />
    <property name="Password" type="String" length="256"
column="Password" not-null="true" />
    <property name="PasswordSalt" column="PasswordSalt" type="String"
not-null="false" length="64" />
    <property name="PasswordFormat" column="PasswordFormat"
type="Int32" not-null="true" />
    <property name="FailedPasswordAttemptCount"
column="FailedPasswordAttemptCount" type="Int32" not-null="true" /

    <property name="LastPasswordChangedDate"
column="LastPasswordChangedDate" type="DateTime" not-null="false"
insert="false" update="false" />
    <property name="LastActivityDate" column="LastActivityDate"
type="DateTime" not-null="true" insert="false" update="false" />
    <property name="IsApproved" column="isApproved" type="Boolean" not-
null="true" />
    <property name="IsLockedOut" column="isLockedOut" type="Boolean"
not-null="true" />
    <property name="LastLockOutDate" column="LastLockOutDate"
type="DateTime" not-null="false" insert="false" update="false" />
    <property name="LastLoginDate" column="LastLoginDate"
type="DateTime" not-null="false"  insert="false" update="false"/>
    <property name="DateCreated" type="Date" column="DateCreated"
insert="false" update="false" />
    <property name="DateModified" type="Date" column="DateModified"
insert="false" />
    <property name="Scrapped" type="Boolean" column="Scrapped"
insert="false" />
    <property name="UrlPhoto" type="String" column="URLPhoto" />
    <property name="PersonalWebSite" type="String"
column="PersonalWebSite" />

    <bag  name="Arts" inverse="true" cascade="all-delete-orphan"
lazy="true">
      <key column="BuzzUserID" on-delete="cascade"/>
      <one-to-many class="XXX.Art, XXX" />
    </bag>

  </class>
</hibernate-mapping>

  Art art = null;
      _UserArtDao.SessionManager.GetCurrentSession().BeginTransaction();

      art = new Art()
     {
       Category = _artCategoryDao.GetById(1),
       Artist = _UserDao.GetByUserName("jack"),
     };
      _ArtDao.SaveOrUpdate(art);
      _ArtDao.SessionManager.GetCurrentSession().Transaction.Commit();