A single place in NHibernate and Sharp Architecture to specify field length for database and validation

Question

I'm building a new system with NHibernate, using S#arp Architecture. I'm new to S#arp, but experienced with NHibernate. One feature I was really hoping to find was a nice way to specify in one place text field lengths that would be carried through to every layer that needs to know the length.

In other words, I use Fluent mapping to specify that the Name field of a Whatsis object is 50 characters. (I turned off automapping because I was still writing mapping overrides for most, if not all classes. I decided just to write the full mapping myself with ClassMap. I want enough detail in the mapping to generate the complete DB schema from it.) Then when I generate the database schema using hbm2ddl, I get a 50-character field length. That's great. But I also want the MVC validators to enforce it automatically. And I'm so greedy I even want the proxy object the NHibernate generates for Whatsis to know about that length in its setter, so if in code I should assign a too-long value, I'll get an exception.

Do I have any hope of achieving this without really overcomplicating my project? This is my first time using Fluent mapping. I thought this was a feature of Fluent, but it looks like it doesn't work that way after all.

Answer 1

You need to use NHibernate Validator as that is the only validator framework that NHibernate hbm2ddl currently supports. Unfortunately it doesn't look like anyone has wired together NHibernate Validator and MVC3 validations. Here is someone else having problems with it:

MVC 3, NHIbernate Validators & Message Interpolator

It should be possible as I've used xVal (predecessor to MVC3 validators) in the past with NHibernate Validator attributes for client-side validation, server-side validation, and schema generation. Someone just needs to invest some TLC to get NHibernate Validator playing nicely with MVC3 validators.