The problem with saying that all validation needs to happen in the Model
is that for practical reasons it does not work very well. The most
common reason is that the Model usually does not deal with all the input
from the request. Some input is intended for the Controller or the View
logic specifically -- but it still needs to be validated and filtered.
Another case is where a simple and generic Model is used because, for
example, only the mix of fields is changing (e.g. CRUD). In these cases
it can be a cleaner design to do validation in the Controller for each
variation and share a common Model.
However, I think the goal should be for the Model to validate all the
data it is interested in.
The MVC pattern is a guideline for dependencies and layer separations
(i.e. domain and presentation), but should not get in the way of good
design. Even those dependencies can be flexed for the needs of the
design. And sometimes it make sense to do some, or even all validation,
in the Controller.
Sam Davey wrote:
I'm not worried as such... but my problem is the flexability of it
all. Don't get me wrong, thats one of the best features of the Zend
Framework, integrating any subsystems I design using ZF into my legacy
system will be incredibly easy compared to the vast majority of other
frameworks available (cakePHP, symfony etc etc).
I was just trying to clarify that the comprehensive tutorial I was
following was not adhering to MVC, and as such I shouldn't use the
examples in the tutorial as a basis for future development since all
of the domain logic was shoved in the controller.
I gather that by quoting 'MVC is simply a matter of keeping the
domain, application and view logic in separate layers' then you agree
with my post. i.e. the controller should not contain any validation or
database interaction since this is domain logic. And the controllers
main purpose is to invoke methods on a the model based on input from
the view.
I understand the principle of MVC... it is a design pattern. Therefore
from my point of view its a moot point to say that ZF is not a strict
MVC framework since the strictness comes from your own design. I just
wanted to make sure that my take on it was correct so that I can
enforce this strictness.
I don't agree with your point that ' we clearly can't discuss about
Model when we don't have ORM
functionality yet to put domain logic into'.
Although ORM would certainly be useful for the majority of Models,
they are certainly not dependant on ORM. Any database interaction can
be done using Zend_Db, granted you sacrifice some development time but
basically achieve the same thing. Besides, some models may not relate
to a database table at all.
From: "Mislav Marohnić" <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
CC: "Sam Davey" <[EMAIL PROTECTED]>, [email protected]
Subject: Re: [fw-general] Advice for Model design
Date: Thu, 21 Sep 2006 16:19:36 +0200
Sam,
Your approach, although basic, is not incorrect... I don't understand
what you're worrying about. MVC is simply a matter of keeping the
domain, application and view logic in separate layers.
Keep in mind that ZF is not a strict MVC framework. Sure it has
Controller and View, but it's more like a "make your own MVC" thing.
And we clearly can't discuss about Model when we don't have ORM
functionality yet to put domain logic into.
