DataMapper ORM v1.8.2

[eluser]michaelfbradley[/eluser]
Hey - Really liking Datamapper.

I have two quick questions.

1. I was wondering if it's possible to define virtual attributes within the model?

Let's say for example I have a users model, and I want to explicitly define a virtual attribute called 'fullname', which uses the firstname and lastname fields from my DB?


2. Is it possible to define different validation requirements for various scenarios within the model? Let's say I have different validation requirements whenever when updating a record, versus creating a record.

Thanks,
M