If I have a simple object hierarchy e.g.
Person
Student : Person
Professor : Person
Dean : Person
that I want to persist using a single Person table, I know that if I keep the discriminator as a string in the Person table, it's straigtforward (discriminator-value="professor", discriminator-value="student", discriminator-value="dean"). But if I want to put the discriminator value into a different table w/ the Person table pointing to it, is this possible?
e.g.
Person table
column = ID (Primary Key, integer, Identity)
column = PersonTypeID (integer, foreign key to PersonType.ID)

PersonType table
column = ID (Primary Key, integer, Identity)
column = TypeName (string, this has the actual type name)

Thanks,
Bill

Use a formula in your discriminator definition in your Person class definition instead of a column mapping:

<discriminator
formula="(select t.TypeName from PersonType t
where t.ID = PersonTypeId)"
type="String"
/>

Then in your subclass definition you can use your string:

<subclass name="Student"
discriminator-value="student">
</subclass>

Hope that helps.