Rails - May 2009 - Using standard validation methods in custom validation metho

Hi,

Is it possible to use standard validation methods in custom validation
methods?
eg:

def check_children
  if children != ""
    validates_numericality_of :children
  end
end

When I run this code I get a no method error:

undefined method `validates_numericality_of'' for
#<Applicant:0x5d1bba4>

Is there any way around this?

Thanks in advance
-- 
Posted via http://www.ruby-forum.com/.

On May 15, 9:15 am, Jim Burgess
<rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org>
wrote:
> Hi,
>
> Is it possible to use standard validation methods in custom validation
> methods?
> eg:
>
> def check_children
>   if children != ""
>     validates_numericality_of :children
>   end
> end
>
> When I run this code I get a no method error:
>
> undefined method `validates_numericality_of'' for
#<Applicant:0x5d1bba4>
>
> Is there any way around this?
>
Not really. validates_numericality_of is a class method that defines
an appropriate validation on a class. You may find the :allow_nil
and :if or :unless options useful

Fred
> Thanks in advance
> --
> Posted viahttp://www.ruby-forum.com/.

Wow, that''s very cool.
I changed the line to:

validates_numericality_of :children, :if => Proc.new { |applicant| true 
if applicant.children !="" }

and that does exactly what I want.
Thanks for your time and help, Fred.

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On 15 May 2009, at 10:24, Jim Burgess wrote:
>
> Wow, that''s very cool.
> I changed the line to:
>
> validates_numericality_of :children, :if => Proc.new { |applicant|  
> true
> if applicant.children !="" }
you can even shorten that to

validates_numericality_of :children, :if => Proc.new { |applicant|  
applicant.children !="" }


Fred
>
>
> and that does exactly what I want.
> Thanks for your time and help, Fred.
>
> -- 
> Posted via http://www.ruby-forum.com/.
>
> >

> you can even shorten that to
> 
> validates_numericality_of :children, :if => Proc.new { |applicant|
> applicant.children !="" }
> 
Cool!
Thanks a lot.
-- 
Posted via http://www.ruby-forum.com/.

Jim Burgess wrote:
> 
>> you can even shorten that to
>> 
>> validates_numericality_of :children, :if => Proc.new { |applicant|
>> applicant.children !="" }
>> 
> 
Looks like a case for allow_nil:

validates_numericality_of :children, :allow_nil => true

The documentation at
http://ar.rubyonrails.org/classes/ActiveRecord/Validations/ClassMethods.html#M000091

mentions

:allow_nil - Skip validation if attribute is nil (default is false). 
Notice that for fixnum and float columns empty strings are converted to 
nil.


Stephan
> Cool!
> Thanks a lot.
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Posted via http://www.ruby-forum.com/.

Thanks for your reply
> Looks like a case for allow_nil:
> 
> validates_numericality_of :children, :allow_nil => true
I created the field ''children'' as a string (can''t
remember why, perhaps
because someone might enter ''none''??), so that
doesn''t work.

Is there any big advantage to changing the field ''children''
into an
interger?
-- 
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Jim Burgess wrote:
> Thanks for your reply
> 
>> Looks like a case for allow_nil:
>> 
>> validates_numericality_of :children, :allow_nil => true
> 
> I created the field ''children'' as a string
(can''t remember why, perhaps
> because someone might enter ''none''??), so that
doesn''t work.
> 
> Is there any big advantage to changing the field
''children'' into an
> interger?
Well, if the column  will hold numbers sure there is an advantage. You 
can perform arithmetic and numeric comparisons. You can sort based on 
the natural order of numbers, not based on lexicographical order.


Stephan

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> Well, if the column  will hold numbers sure there is an advantage. You 
> can perform arithmetic and numeric comparisons. You can sort based on 
> the natural order of numbers, not based on lexicographical order.
Yeah, that''s true enough.
I''ll get it changed as I want to do everything properly.
Thanks for your help.
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