Why belongs_to does not like validation?

Rails
1

This works :

class Recipe < ActiveRecord::Base
belongs_to :category
end

But (when I add validation) this does not work :

class Recipe < ActiveRecord::Base
belongs_to :category
validates_length_of :category, :within => 6…20
validates_uniqueness_of :category, :message => “already exists”
end

thank you

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2

On 3/28/06, mlotfi [email protected] wrote:

class Recipe < ActiveRecord::Base
belongs_to :category
validates_length_of :category, :within => 6…20
validates_uniqueness_of :category, :message => “already exists”
end

thank you

:category is not a database attribute. Validations occur only on
database attributes, so use :category_id.

–
Rick O.
http://techno-weenie.net

3

mlotfi wrote:

validates_length_of :category, :within => 6…20
validates_uniqueness_of :category, :message => “already exists”
end

You need the category validations in the Category model, not in the
Recipe model.

If you want to validate that there is a valid category for a Recipe you
are creating, you want something like

 validates_associated :category, :message => "no such category"

–

Ray

4

title is an attribute of the table recipes.
here is what I have :

class Recipe < ActiveRecord::Base
belongs_to :category
validates_length_of :title, :within => 6…20
validates_uniqueness_of :title, :message => “already exists”
end

But when I try to add a new recipe I get this error :

NoMethodError in Recipe#create
Showing app/views/recipe/new.rhtml where line #17 raised:

You have a nil object when you didn’t expect it!
You might have expected an instance of Array.
The error occured while evaluating nil.each

Extracted source (around line #17):

14:


15: Category:

16:
17: <% @categories.each do |category| %>
18:
19: <%= category.name %>
20:

RAILS_ROOT: ./script/…/config/…

Application Trace | Framework Trace | Full Trace
#{RAILS_ROOT}/app/views/recipe/new.rhtml:17
#{RAILS_ROOT}/app/controllers/recipe_controller.rb:11:in `create’

–
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5

That means that @categories is nil. Did you set it in the controller?

6

Also, you could use the form helper collection_select to create that
select menu:

<%= collection_select ‘recipe’, ‘category_id’, @categories, ‘id’, ‘name’
%>

7

mlotfi wrote:

yes I did, in recipe_controller.rb :
def edit
@recipe = Recipe.find(@params[“id”])
@categories = Category.find_all
end

And you have some independent means of knowing that Category.find_all
returned some results?

8

yes I did, in recipe_controller.rb :

class RecipeController < ApplicationController
layout “standard-layout”
scaffold:recipe

def create
          @recipe = Recipe.new(@params['recipe'])
          @recipe.date = Date.today
            if @recipe.save
               redirect_to :action => 'list'
            else
               render_action 'new'
	end
    end

def new
	@recipe = Recipe.new
	@categories = Category.find_all
end

def list
	@category = @params['category']
	@recipes = Recipe.find_all
end

def edit
	@recipe = Recipe.find(@params["id"])
	@categories = Category.find_all
end

def delete
             Recipe.find(@params['id']).destroy
             redirect_to :action => 'list'
    end

end

–
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9

I am sorry I did not understand your question.
I am just doing what in the cookbook tutorial, as I said before without
validation everything worked fine.

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10

mlotfi wrote:

I am sorry I did not understand your question.
I am just doing what in the cookbook tutorial, as I said before without
validation everything worked fine.

Are there any categories in the Category table?

11

the table is called categories it has an id and name columns.

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12

mlotfi wrote:

the table is called categories it has an id and name columns.

Are there any rows in the table? If there are no rows then the
Catgories.find_all in your statement:

 @categories = Categories.find_all

will return nil.

–

Ray