similar to: Help setting up relationships needed

Consider the following scenario: Book has_and_belong_to_many Category. In other words, a category may have a lot of books, and a book can have more than one category. What is the best practice to query all books related to some specified categories. For example, if I have following books "From Java To Ruby" - Category: Java, Ruby "Ruby Programming" - Category: Ruby

Hi there, I''m currently creating a simple (at least so I thought) structure of user favorites. Basically users can add certain ''objects'' to their list of favorites. Here is my current structure (simplified) class User has_many :favorites end class Book belongs_to :favorites end class Favorite belongs_to :user has_one :book end The table favorite just has a two

It seems that using a join model that joins with two has_many''s will fail to generate proper SQL class StudentSemesterRecord < ActiveRecord::Base belongs_to :semester has_many :discipline_records, :through => :semester end class Semester < ActiveRecord::Base has_many :student_semester_records has_many :discipline_records end class DisciplineRecord <

Suppose I have a site about books and authors, and users can leave comments on either a book or an author. I''d want to have a table called "comments", which could belong to either an author OR a book. In my structure I wouldn''t be sure whether to include an "author_id" or a "book_id", or both. What would be the best way to handle this

People, In the cookbook eg, categories has_many recipes but in a book eg, book has_one description - doesn''t that mean that the id of the description should be the same as the id of the book (instead of having it''s own "description_id" in the book table? Thanks, Phil. -- Philip Rhoades Pricom Pty Limited (ACN 003 252 275 ABN 91 003 252 275) GPO Box 3411 Sydney

I''m trying to use has_many :through, since my join model deserves being more than just an intersection table. But when I try to break the association, the break only seems "temporary": Let''s say my two tables are Users and Colors, and the join model is Favorites. user = Users.find(1) user.colors.length >> 2 c = user.colors.first >> #<Color:....>

Hello, I''m a newbie to aaf and rails and I hope anyone can help me with this. I have the following Models: class Project < ActiveRecord::Base acts_as_authorizable acts_as_audited :except => [:created_by, :updated_by ], :user_class_name => ''AuthenticatedSystem'', :user_method => ''current_user'' acts_as_ferret :fields => {:name =>

Hi folks, I am in the process of converting an existing non-rails application to rails, and am not sure what the best approach would be for specifying the relationship between the two sets of data. I''ll describe the existing table structures first. Table 1: Urls Each url has a unique id and two lists of Phrases, these are currently setup as varchars with "," delimitation -

Having a devil of a time finding records in a self-referencing has_many table relationship. Everything is working find looking at the has_many and the belongs_to relationship. But, when I try to find all "orphans", records that are neither a parent nor a child, I can not find a query that work in ActiveRecord. This query works in MySQL: SELECT * FROM templates LEFT JOIN templates

Hi I have a has_many :through. It''s a basic mapping of Project id .... User id .... TeamMembers project_id user_id role What I would like to do is have different roles so I can have in the project model has_many :core_members, :through => :team_members, :source => :user but I would like to limit this to only those with the "core" role in the team members table for

Good evening list members, I have the following model: class Author < ActiveRecord::Base has_many :authorships has_many :books, :through => : authorships end Should I be able to do the following? Author.find(:first).book_ids = [1,2,3] I ask, because it doesn''t. The docs state that it should, but it doesn''t specialise in the case of a :through This

I''d like to use :through to create a web of associations like: class Thing < ActiveRecord::Base has_many :child_things, :through => :thing_thing has_many :parent_things, :through => :thing_thing, :some_other_option? end class ThingThing < ActiveRecord::Base belongs_to :thing belongs_to :child_thing, :class_name => ''Thing'', :foreign_key =>

I have two tables and a join table for them e.g. books, authors in a many to many relationship (habtm) and a join table books_authors. I can successfully search for a book that has "author.id = 2 OR author.id = 4" but I am unable to search for "author.id = 2 AND author.id = 4" This is because the result of all the joins only has one author.id column so no single row has

Hi, How do I associate two different tables which have a lookup id (table) as common. I tried the has_many :table2, :through => look_up_table in my table1 model. Any hints? Thanks, Hari -- Posted via http://www.ruby-forum.com/.

I have this code that is using svn externals with rails EDGE working fine for the past couple of months. A couple of days ago, this code died. Even after deleting vendor/rails, this code doesnt work: class Tag < ActiveRecord::Base has_many :taggings has_many :events, :through => :taggings has_many :users, :through => :taggings end class User < ActiveRecord::Base # Virtual

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"

I am trying to do a simple find through the current_user but get an exception. Either someone spiked my Starbucks coffee and I am screwing up all over the place or there is something wrong. def index @league = current_user.leagues.find(13) end # Error LocalJumpError in Admin/schedule todosController#index no block given If I pass a block to it it works fine, but it is just messy: =====

I am having a problem with doing a :through that goes back to the same table. The following are my two classes: >>>>> class User < ActiveRecord::Base has_many :spanks has_many :spanked, :through => :spanks, :source => :spanked_user has_many :was_spanked_by, :through => :spanks, :source => :user end class Spank < ActiveRecord::Base belongs_to :spanker,

belongs_to :through Why is that not possible? We should have: Street belongs_to :city belongs_to :country, :through => :city -- Posted via http://www.ruby-forum.com/.

I just took my HABTM and turned it into a :through since my join table has another "non-joiny" attribute. I went from this: has_many_and_belongs_to :jobs, :join_table => ''tablename'', :foreign_key => ''x'', :association_foreign_key => ''y'' to this: has_many :jobs, :through =>