Rails - Jan 2009 - What is wrong with validates_presence_of :my_association ?

Category.has_many :products

Let''s say a product must belong to a category. I know it is recommended
to do the following:

class Product
validates_presence_of :category_id
end

But, as we all know, this is a pain for new records, meaning what if the
associated category is a new record?

I''ve been meaning to ask this, but what''s wrong with doing the
following:

class Product
validates_presence_of :category
end

I never understood why that was so wrong. So I wanted to ask and see if
I am missing something. What do you think? Thanks for your help!
-- 
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That will check the value for a field called category, not an  
association.
-----
Ryan Bigg
Freelancer
http://frozenplague.net







On 09/01/2009, at 10:43 AM, Ben Johnson wrote:
>
> Category.has_many :products
>
> Let''s say a product must belong to a category. I know it is  
> recommended
> to do the following:
>
> class Product
> validates_presence_of :category_id
> end
>
> But, as we all know, this is a pain for new records, meaning what if  
> the
> associated category is a new record?
>
> I''ve been meaning to ask this, but what''s wrong with
doing the
> following:
>
> class Product
> validates_presence_of :category
> end
>
> I never understood why that was so wrong. So I wanted to ask and see  
> if
> I am missing something. What do you think? Thanks for your help!
> -- 
> Posted via http://www.ruby-forum.com/.
>
> >

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* Ben Johnson <rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
[2009-01-09 01:13:53 +0100]:
> 
> Category.has_many :products
> 
> Let''s say a product must belong to a category. I know it is
recommended
> to do the following:
> 
> class Product
> validates_presence_of :category_id
> end
> 
> But, as we all know, this is a pain for new records, meaning what if the
> associated category is a new record?
> 
> I''ve been meaning to ask this, but what''s wrong with
doing the
> following:
> 
> class Product
> validates_presence_of :category
> end
In this case you may need validates_associated or write your own
validation by def validate.
> 
> I never understood why that was so wrong. So I wanted to ask and see if
> I am missing something. What do you think? Thanks for your help!
> -- 
> Posted via http://www.ruby-forum.com/.
> 
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> To post to this group, send email to
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-- 
jan=callcc{|jan|jan};jan.call(jan)

Ben Johnson wrote:
> Category.has_many :products
> 
> Let''s say a product must belong to a category. I know it is
recommended
> to do the following:
> 
> class Product
> validates_presence_of :category_id
> end
> 
> But, as we all know, this is a pain for new records, meaning what if the
> associated category is a new record?
> 
> I''ve been meaning to ask this, but what''s wrong with
doing the
> following:
> 
> class Product
> validates_presence_of :category
> end
> 
> I never understood why that was so wrong. So I wanted to ask and see if
> I am missing something. What do you think? Thanks for your help!
It isn''t wrong, it''s the right way to do it. You just have to
assign a category object when building a new Product.

-- 
Rails Wheels - Find Plugins, List & Sell Plugins - http://railswheels.com

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