Validation help please

Hi,

Can anyone take a look at this… i’ve been banging my head on the
wall for several days trying to figure this out. The validation is
bypassed as it seems its not evaluating :question_type == “standard” to
true in the model.

Model:
validates :question_type, :presence => true
if :question_type == “standard”
validates :question, :presence => true

Controller:
def create
@question = Question.new(params[:question])
if @question.save
if @question.question_type == “standard”
flash[:success] = “Question created!”
redirect_to @question
else

new.html.erb:
<%= f.submit ‘Save’, question_type: “standard” …

On 1 March 2013 13:20, Dave C. [email protected] wrote:

  validates :question,        :presence   => true

Is that code just inline in the model? If so then it is only executed
once, when the code is loaded, so the if statement is not tested for
each object being validated. Have a look at the Rails Guide on
ActiveRecord Validations and Callbacks to see ways that you can
accomplish what you want.

Colin

Hi Dave,

I believe you should do something along the lines of

Model:

validates_each :question do |record, attr, value|
record.errors.add attr, ‘The question is not present!?’ if
value.blank? and record.question_type==“standard”
end

plz correct me if I’m wrong, Colin :slight_smile:

cheers,
Walther

Den 01/03/2013 kl. 14.20 skrev Dave C. [email protected]:

On 1 March 2013 13:46, Walther D. [email protected] wrote:

plz correct me if I’m wrong, Colin :slight_smile:
It might be easier to use :if

Colin

On Friday, March 1, 2013 1:20:24 PM UTC, Ruby-Forum.com User wrote:

if :question_type == "standard"
  validates :question,        :presence   => true
...

This code is evaluated when the model is loaded. It compares the symbol
:question_type to the string ‘standard’ (which are of course never
equal)
and so doesn’t add the validation.
You want the choice of whether to apply the validation or not to be
taken
when the model is about to be validated. The standard way of doing that
is
with the :if option

validates :question_type, :presence => true
validates :question, :presence => true, :if =>
:standard_question?

will call the standard_question? method and only enforce the presence
validation on question if the method returns true. There is also a
lambda
form

validates :question, :presence => true, :if => lambda {|record|
record.question_type == ‘standard’}

Fred

Frederick C. wrote in post #1099720:

On Friday, March 1, 2013 1:20:24 PM UTC, Ruby-Forum.com User wrote:

if :question_type == "standard"
  validates :question,        :presence   => true
...

with the :if option

validates :question_type, :presence => true
validates :question, :presence => true, :if =>
:standard_question?

will call the standard_question? method and only enforce the presence
validation on question if the method returns true. There is also a
lambda
form

validates :question, :presence => true, :if => lambda {|record|
record.question_type == ‘standard’}

Fred

Thanks Fred,
Got this error
undefined method `standard_question?’ for #Question:0x007f947ddb2e00
Do I need to write a standard_question method

(I’m beginner)

Ok,

Thank you. I read Rails Guide on ActiveRecord Validations and
Callbacks, specifically Conditional Validation.

So,
validates :question, :presence => true, :if => “question_type.blank?”
placed inline in model should be the simplest way to do this. It does
not work however. My lack of understanding seems to be related to how I
specify question_type in the condition?

As you can see i’m still on the bottom of the steep part of the learning
curve.’

Thanks for the help

Lambda method works, although I don’t understand it :slight_smile:

Thanks!!

Dave

Thanks again,

Is there a way to add a message if validation fails using lambda method
(I am using Lambda method until I can figure out why
validates :question, :presence => true, :if
=>:standard_question?
generates
undefined method `standard_question?’ for #Question:0x007f947ddb2e00)

Dave, you have to add an instance method “standard_question?” to your
model

def standard_question?
end

from the url below you can see that you can pass a :message param to
customize the error message

http://guides.rubyonrails.org/active_record_validations_callbacks.html#message

On Friday, March 1, 2013 2:58:53 PM UTC, Ruby-Forum.com User wrote:

form

Yes - it’s up to you to write a standard_question? method. The lambda
saves you having to have the condition in a separate method but can make
your validation look more cluttered (especially for more complicated
conditions).

Fred

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