[Dbix-class] Optimistic locking

[Dan Horne]

On Behalf Of Matt S Trout 
> Dan Horne wrote:
> > Hi
> >
> > I'd like to implement a form of optimistic locking in one of my apps.
> Rather
> > than handle this manually in the app itself, I'm hoping to reduce the
> coding
> > overhead by incorporating the logic in a DBIC component. The basic steps
> > are:
> >
> > 1. Generate a pseudocolumn that contains a hash of the current row (or
> > allrows if $rs->all).
> > 2. At some point in the future, a user will try to save the record via a
> > webform. The overridden update method will query the original row and
> > recompute the hash. If the two hashes don't match, an exception will be
> > thrown.
> >
> > So, my question is: Is there any way to create such a pseudocolumn that
> can
> > be populated as a result of the values of the other columns?
> 
> Why do you need a "pseudocolumn" ?
> 
> It's just a perl object. Add an accessor ...

Yes, wrong terminology on my part. Ok, I'm still coming to grips with
writing components. Specifically, I can't see how I can automatically add
the checksum to each row that gets fetched.