similar to: Validating an association

Hi, First post, please be gentle! I couldn''t find any mention of this already I''m using ActiveRecord and I want to enforce mutual exclusivity on a has_and_belongs_to_many. A concrete example: I have a User which can have one or more Roles (student, tutor, headmaster, administrator etc). However if a user is a student they cannot hold any other role. I was hoping to find

problem: validation error is not functionning in callback callback for many-to-many association: # keyword.rb :before_add => :reject_self_related def reject_self_related(related_keyword) if (related_keyword == self) # this does not work: errors.add(:name, "Relating a keyword to itself is forbidden!") raise "Relating a keyword to itself is

Hi, I''m currently having the situation where I have to implement a polymorphic has_and_belongs_to_many by introducing an in between model that handles all the "has_many :as" and "belongs_to :polymorphic" association implementations... and is not doing anything else. Thing I don''t like it here is, I am unnecessarily loading AR instances only to execute SQL

Someone asked me about the history of the method naming in activerecord and I wasn''t sure where to point them. For example, there was early criticism noted of has_and_belongs_to_many in this old post from 2005: http://hans.fugal.net/blog/2005/10/03/habtm/ I was mentioning that many_to_many is not used because there are a few different ways of doing that via has_many :through and

I am trying to create a record with association. Within the create method, I would also like to pre-populate dependent (has_many) records from a template in the database. The child records are <u>mysteriously rolled back </u> if I insert them in a loop. If I try to insert a single child record, it works.I have read the books and tried to google my way out of this but am at a dead

If I have a class, Asset, which has and belongs to many associated Asset objects, how do I do this? has_and_belongs_to_many :associated_assets, :class => "Asset", :foreign_key => ?????, :association_foreign_key => ????? Right now, my table has a :first_asset_id and a :second_asset_id, but I don''t see how the objects themselves are supposed to distinguish one from the

I have two objects that are associated in the following way: class Class1 < ApplicationController has_and_belongs_to_many :class2s has_and_belongs_to_many :otherClasses end class Class2 < ApplicationController has_and_belongs_to_many :class1s has_and_bleongs_to_many :otherClasses end Now, when I run the following query, @objects = Class1.find(:all, :conditions

Hi to all, I''m needing some help here ... I want to do an extension on a has_and_belongs_to_many to build a custom add method to the association. i have a table locations that has a many-to-many association with a tags tabel using a locations_tags table. i want to add a method to the Location has_and_belongs_to_many association so that i can do something like this on the location

Good Friday Everyone :-). These are my models: Problem -> has_and_belongs_to_many :tags Tag -> has_and_belongs_to_many :problems Now if a tag does not exist and I create it and associate it to the problem it works self.tags << Tag.create(:name => tag) But if I have the tag already in the DB and just want to link it to another problem it does not really like me. I do it

A concrete example: We''re building a system to organize the information about workshops being held in various conventions. A convention has more than one workshop, and each workshop can be held in more than one convention. Also each workshop has a host, who is specific to a workshop being held in a specific convention. For example, Matz may host an "Introduction to Ruby"

Hi all I''m working on a Custom Formbuilder. I want it to create me with a single method call checkboxes for a given HABTM association. My model looks like this: [code=ruby]class Member < ActiveRecord::Base has_and_belongs_to_many :preferred_music_styles, :class_name => ''MusicStyle'', :join_table =>

Hi, Song has_and_belongs_to_many :people accepts_nested_attributes_for :people Person validates :uniqueness => true If person record not present, nested attributes working great! in rails way. i.e., inserting into songs, people and people_songs table correctly. I am interested in:- *If there is person exist, it should skip insertion into people table but data should be inserted in songs and

I''m trying to order a find through a has_many association. I have a model called SalesOrder. Each sales order has things like amount, description, etc. I use the following to get the Sales Orders: @sales_orders = SalesOrder.find(:all) And I display them with: <td><%= link_to sales_order.id.to_s, :action => ''show'', :id => sales_order.id

I have a form_remote_tag that calls a method to print out a csv file for download. If I tell the form_remote_tag to update a div the data comes up in that div, but otherwise I can''t get the browser to acknowledge the sent file. >From view: <%= form_remote_tag :url => {:action => "csv_dump" }%> <%= submit_tag "Download Complete List" ,:name

i have a model with this: file_column :image validates_file_format_of :image, :in => ["gif", "png", "jpg"] If inthe form the user not insert the image i receive an error. If i remove: validates_file_format_of :image, :in => ["gif", "png", "jpg"] it works. Is possible do the validation only when user insert the image in form? i

As per http://rails.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html Possible callbacks are: before_add, after_add, before_remove and after_remove. Should any of the before_add callbacks throw an exception, the object does not get added to the collection. Same with the before_remove callbacks; if an exception is thrown the object doesn‘t get removed. However, when the add

Hi, I am trying to restrict duplicate has_and_belongs_to_many associations. I tried to find support for a association validation for duplicates but couldn''t find anything. I understand I could use :uniq=>true on the model association but this would only prevent it from displaying duplicates, I want to stop duplicate associations being inserted in the first place. I have a vague

I''m trying to write an interface for editing many-to-one relationships with AJAX. Picture the to-do editor in Backpack (and, to a lesser extent, Basecamp) and you''ll have a good idea of what I''m trying to do. I''ve almost got everything working: the ''edit'' link hides the stored data and replaces it with a form, and the data is updated in the

Hi. I have a couple of best practices questions regarding polymorphic associations, naming join tables and user permissions. Currently I have implemented the user authentication model from the rails recipes book. Basically it goes something like this: MODEL CLASSES: class User < ActiveRecord::Base has_and_belongs_to_many :roles end class Role < ActiveRecord::Base

Hi, I am new to Ruby and Rails programming and am having difficulty with the following scenario... Consider the following model: class Studio < ActiveRecord::Base has_many :movies has_and_belongs_to_many :actors end class Movie < ActiveRecord::Base belongs_to :studio has_and_belongs_to_many :actors end class Actor < ActiveRecord::Base has_and_belongs_to_many :studios