How to map a discriminator value to a property ?

How would you go about mapping a discriminator value (in a single-table inheritance strategy) to an entity property? Because of a query that I need I introduced a separate property: .Add( TLinq.StartsWith( 'PageType', cPageMC ) ). But that property holds the same values as the discriminator-value column, so why not use that one.

That's not possible for now, unfortunately. It's something that could be added indeed, but as a read-only property. 

Is it possible to Access the discriminator value now?
I need our DiscriminatorColumn within a AureliusDataset, so it would be nice to access this easily (maybe with an additional Rtti-Prop).

No, I'd suggest adding it as a feature request so we can track it: