[Dbix-class] Re: DBIx::Class::ResultSet::RecursiveUpdate - announcement and RFC

[Matt S Trout]

On Thu, Oct 02, 2008 at 08:18:59AM +0100, Carl Franks wrote:
> 2008/10/2 Zbigniew Lukasiak <zzbbyy at gmail.com>:
> > On Thu, Oct 2, 2008 at 2:40 AM, Matt S Trout <dbix-class at trout.me.uk> wrote:
> >> On Wed, Oct 01, 2008 at 09:38:07AM +0200, Zbigniew Lukasiak wrote:
> >>> The example that I am mostly concerned with is:
> >>>
> >>> $cd_rs->recursive_update( { title => 'New Title', artist => { name =>
> >>> 'New Name' } } )
> >>>
> >>> Now when traversing the relation from cd to the artist I get the
> >>> artist resultset with the PK constrained in the ->{cond}.  There is
> >>> just one artist that the cd 'belongs_to' - and that artist should be
> >>> updated.  But there is no PK passed in the parameters - so if we just
> >>> look at the parameters we would  conclude that this would require a
> >>> ->create call.
> >>
> >> Ah, because the artist is about to be changed?
> >>
> >> In that case you should create the artist separately and then assign it
> >> I think, which again avoids the problem.
> >>
> >
> > Perhaps I did not explain it enough - I want that call to result in an
> > update not a create.  An update to the only artist that 'belongs_to'
> > the cd.
> 
> ( /me steps into a minefield )
> 
> I would suggest that if it's an update, you should already have the
> artist PK - keep ahold of it when you're initially getting the vales
> from the DB.
> 
> Then, when you're doing the update, verify the PK hasn't changed (or
> maybe allow it to be configured to allow rel ID changes).
> 
> I know FormFu doesn't do that, it can just follow the relationship
> name, so you don't need a hidden field for the related PK - but I feel
> it's more flexible to handle traversing the relationships ourselves,
> rather than using a core DBIC recursive-update.

Especially given there are probably multiple different behaviours you'll
want in different situations.

Agree entirely.

fireartist++

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