Question

I have an NHibernate entity called Owner that has a SSN column and a TaxID column in the database, and I would like to conditionally map one of those two values to a more generic property on the Owner entity based on the value of a different property, StructureType. So, if the StructureType is “I”, I want to map the SSN value to the generic property, and if its “C” I want to map the TaxID value to the generic property. Is this possible using Fluent NHibernate (or even regular NHibernate)? The Owner entity is a read-only entity, nothing will be written back to the database.

Answer 1

I was able to solve this using a Formula in Fluent NHibernate:

Map(x => x.Identification)
.Formula("CASE WHEN StructureType = 'I' THEN SSN ELSE TaxID END");

(In my original post I said it was between ‘I’ and ‘C’ but is in fact just between ‘I’ and every other type)