Hi,

I have two entities: Person and AdminPerson. A person is any person registered in the database. An AdminPerson is a person that has a login and password.

I have defined this inheritance as table per subclass. When I try to load an instance of a superclass (Person) I get an instance of the subclass (AdminPerson) if it exists.

I would like to get an instance of the Person even if the Person is an AdminPerson. I tried to define polymorphism="explicit" but it doesn't have any effect.

What's the best way to accomplish this?


Hibernate version:
1.2.0.Alpha2

Mapping documents:

something like this:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0" schema="dbo">
<class name="Domain.T_Person" lazy="false" table="PERSON" polymorphism="explicit">
<id name="ID" type="Decimal" column="USERID">
<generator class="identity" />
</id>
<property name="FirstName" column="FirstName" type="String" />
<property name="LastName" column="LastName" type="String" />
<joined-subclass name="Domain.T_AdminPerson" table="ADMIN_PERSON">
<key column="USERID"/>
<property name="Login" column="UserName" type="String" />
<property name="Password" column="Password" type="String" />
</joined-subclass>
</class>
</hibernate-mapping>


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

T_Person person = session.Get<T_Person>(1);

Name and version of the database you are using:

MS Sql Server 2000

For some reason you are against the current OOP wisdom...
In your case you should break the hierarchy and add the extra data for AdminUser as a one-to-one relationship to the person.

HTH,
Radu

Thank you for your reply. But the real problem is that I have another entity that has a reference to a Person:

[Serializable]
class T_Request()
{
.
.
public DateTime RequestDate
public T_Person RequestedBy

.
.

}

I want to serialize the T_Request and I'm getting the message "Domain.T_AdminPerson was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically". Of course, this occurs only if the Person is an AdminPerson.

The XmlInclude attribute is valid only on class, struct, method, interface. This is the reason why I would like to "force" the superclass. Do you have any suggest?

Well, this is not C++ with objects on the stack which can be "sliced"...
Some alternatives:
1. study the documentation, it should be able to serialize a polymorphic collection, maybe requires more work on your part.

2. "brute force" solution (I consider it ugly): build a conversion operator or a constructor able to convert an AdminPerson back to Person. Iterate the resulting collection and replace AdminPerson instances with newly created copies of Person.

3. My previous post was already explaining you how to remove the inheritance hierarchy and add Admin part as a separate object in an one-to-one relationship, so your collection will be only of Person objects.

I tend to preffer 1., try to search for info on how to serialize a polymorphic collection.

HTH,
Radu

-- duplicate posting, please disregard --