[Catalyst] catalyst tutorial: MyAppDB/Book.pm vs. MyApp/Model/Book.pm

[John Napiorkowski]

--- Matt S Trout <dbix-class at trout.me.uk> wrote:

> On Tue, May 15, 2007 at 03:47:57AM -0700, mla wrote:
> > I find the Rails ActiveRecord interface pretty
> appealing:
> > 
> >  
>
http://ar.rubyonrails.com/classes/ActiveRecord/Base.html
> 
> DBIC's interface is not dissimilar although it
> favours data structures
> for query descriptions rather than raw SQL.
>  
> > I like the notion of protected fields
> (attr_protected and
> > attr_accessible) to allow mass assignment directly
> from the
> > request parameters.
> 
> This is perl.
> 
> my @ok = qw(foo bar baz quux);
> 
> my %set; @set{@ok} = @{$c->req->params}{@ok};
> 
> $dbic_obj->update(\%set); # but gods please validate
> first for production
> 
> > I like how if you fetch columns that don't exist
> in the table
> > the object becomes read-only by default.
> 
> That's neat, although I prefer tools that presume I
> know that I'm doing.
> 
> > And the find() interface seems nice, where
> basically the
> > select is just broken into its components (e.g.,
> condition,
> > order, group, limit, offset). I know they add a
> bunch of
> > helper fetch methods through their autoload
> mechanism.
> 
> Yeah, I find this kinda funny. Rails guys go "look,
> LOOK" about the equiv. of
> 
> find_by_login($login)
> 
> DBIC just handles
> 
> find({login => $login})
> 
> which saves autoload madness at the cost of ... TWO
> CHARACTERS ...

BTW, if this was something some people really wanted I
don't think it would be too hard to create as a DBIC
component.  You'd just be auto creating a bunch of
relationships via __PACKAGE__->add_relationship (I
think).  The biggest issue I have is that (from what I
understand) they assume all your unique constraints
are single key.  I sometimes have multikey uniques for
when it makes sense to me.  So I'm not sure what we'd
want to call it ->find_by_key1_and_key2?  Doing
->find({key1=>...,key2=>...}) seems more consistent to
me and has the benefit of being easy to work with if
you are writing a lot of common code that find stuff
via introspection of the data.  So I wouldn't find it
so useful.  --john


> 
> > So with that design you'd get the centralized
> validation, which
> > is most critical to me, but then you could use SQL
> freely
> > and get back a collection of read-only active
> record objects
> > if you did fancy stuff.
> 
> You -can- pass a custom chunk of SQL to DBIC for the
> where clause and have
> it Just Handle It. The fact that most people choose
> not to is, however, a
> hint as to where the better engineering practice
> lies :)
> 
> > I'll read through DBIx::Class some more. The thing
> where the
> > models are used through the schema seemed weird to
> me and I don't
> > fully understand it yet. I'd really like to be
> able to "use Try::User"
> > and be able to create and update it rather than
> going through an
> > explicit db schema layer. I guess I could create
> another object
> > that wraps around the DBIx::Class module or
> something.
> 
> Under Cat you'd just be doing $c->model('DB::User')
> and everything would work.
> 
> The reason for the explicit schema object is to
> handle multiple connections
> elegantly (see recent blog madness for the nasty
> hacks used to make AR sort
> of handle it if you change all your code to use a
> different syntax).
> 
> If you're sure you only need one connection, DBIC
> -will- let you set the
> connection at the class level. It's just kinda gross
> so people generally don't.
> 
> -- 
>       Matt S Trout       Need help with your
> Catalyst or DBIx::Class project?
>    Technical Director    Want a managed development
> or deployment platform?
>  Shadowcat Systems Ltd.  Contact mst (at)
> shadowcatsystems.co.uk for a quote
> http://chainsawblues.vox.com/            
> http://www.shadowcatsystems.co.uk/ 
> 
> _______________________________________________
> List: Catalyst at lists.rawmode.org
> Listinfo:
> http://lists.rawmode.org/mailman/listinfo/catalyst
> Searchable archive:
>
http://www.mail-archive.com/catalyst@lists.rawmode.org/
> Dev site: http://dev.catalyst.perl.org/
> 


__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com