NoMethodError

rubyonrails-talk
1

Hi I'm having a NoMethodError

NoMethodError in Admin/updateController#index

undefined method `find' for #<Tag id: nil, name: "", rank: nil, parent_id: 0>

in the model I have

  def find_subcategory(subcategory)

     subcategory_id = self.find(:all, :conditions => [ "subcategory = ?", subcategory ])     return subcategory_id.id

  end

in the controller I have

@tags = Tag.new @category_id = @tags.find_category(products[i].elements["category"].text)

I don't understand why the find method isn't defined, isn't find method predefined for every active record object. Any help greatly appreciated.

Thanks.

2

By the looks of things, Tag is inherting correctly from ActiveRecord::Base, but could you show us your whole model anyway? There’s find_category missing from what you gave us and I’m sure that:

products[i].elements[“category”].text

could be done much more nicer if I knew what you were trying to do! I think you’re iterating through the products, finding the category for each and then the text for that category and then doing a find on it. I don’t fully understand why you’re doing the find if you already know what the category is!

3

The model looks like this

class Tag < ActiveRecord::Base

  has_and_belongs_to_many :products,     :join_table => 'products_tags'   validates_presence_of :name validates_uniqueness_of :name   acts_as_tree :order => '-rank DESC'

  def find_category(category)

  # if tag for given category exists return the id, else create it and return id       category_id = self.find(:all, :conditions => [ "category = ?", category ])       if category_id then          return category_id.id        else           new_category = self.new           new_category.name = category           new_category.save           category_id = self.find(:all, :conditions => ["category = ?", category])           return category_id.id        end

  end

  def find_subcategory(subcategory)

     # if tag for given subcategory exists return the id, else create it and return id

     subcategory_id = self.find(:all, :conditions => [ "subcategory = ?", subcategory ])      if subcategory_id then         return subcategory_id.id       else          new_subcategory = self.new          new_subcategory.name = subcategory          new_subcategory.save          subcategory_id = self.find(:all, :conditions => ["subcategory = ?", subcategory])          return subcategory_id.id       end   end

end

products[i].elements["category"].text

Comes from an xml file, that I'm importing, I'm doing a find to see if the category already exists in the database before I insert the product so that I can link the product with an appropriate category, and subcategory.

4

The model looks like this

class Tag < ActiveRecord::Base

has_and_belongs_to_many :products,    :join_table => 'products_tags' validates_presence_of :name validates_uniqueness_of :name acts_as_tree :order => '-rank DESC'

  def find_category(category)

  # if tag for given category exists return the id, else create it and return id      category_id = self.find(:all, :conditions => [ "category = ?", category ])

find is a class method, not an instance method. from an instance
method you have to say Tag.find or self.class.find. However, what I think you want to do here is make the find_category
method a class method.

Fred

5

Ahh good pick Fred!

6

If you wanted to use "find_category" as a method of Model "Tag", then you must also define your method as such:

        def self.find_subcategory(subcategory)                 subcategory_id = self.find(:all, :conditions => [ "subcategory= ?", subcategory ])                 return subcategory_id.id         end

I just put "self." infront of the method name.

7

Thanks for the help, I'll see if I can get this working when I get a chance later on, however this does make sense.