similar to: display variable from a relationship

I was able to create a has_and_belongs_to_many relationship for my app, but now I''m not too sure how to write queries for it. Basically, I have a table ''courses'' that has_and_belongs_to_many ''categories'' and vice versa So I''m trying to figure out how I would find only the courses that belong to a category that I specify. Let''s

If Product and Category models are in a habtm relationship, i.e. class Product < ActiveRecord::Base has_and_belongs_to_many :categories end class Category < ActiveRecord::Base has_and_belongs_to_many :products end I want a piece of code to be executed every time a product is connected to a category. Where do I put this code? Which callback (and on which model) will be triggered? Any

Hey Everyone! I have a newsletter system that contains a multitude of different newsletters. In this case three but the system allows the user to add more. Every user can be subscribed to any amount of given newsletters. So what I did was I created a user model, newsletter model, and subscription model. The subscription model belongs to one user and one newsletter. However,

Hi, I have a many-to-many relationship between dishes and ingredients class Dish < ActiveRecord::Base has_and_belongs_to_many :ingredients end class Ingredient < ActiveRecord::Base has_and_belongs_to_many :dishes end I have a join table dishes_ingredients now when i access my_dish.ingredients, i get a list of what looks like Ingredient objects, but the but they don''t have

So i have one table of data, each data object has two owners from the users table. so it''s data table id owner1_id owner2_id --------------------- 5 1 2 10 1 2 owner table id name --------------- 1 bob 2 cornholio so when i pull records from the data table for owner1_id how would i access the name field of owner id 2? -- Posted via

trying to set up a "has_and_belongs_to_many" relationship would very much appreciate the help, not sure what im doing wrong at all. Scheme.rb class Scheme < ActiveRecord::Base validates :schemename, :presence => true belongs_to :user has_many :levels, :dependent => :destroy has_and_belongs_to_many :works end Work.rb class Work < ActiveRecord::Base

Hi everyone, I have the following problem, maybe someone can help me figure out what to do. To simplify my situation, I''m going to make an example of what I need, this is not the real app structure. Let''s suppose we have three models, Library, Author, Book. Manager has_and_belongs_to_many :area_managers AreaManager has_and_belongs_to_many :managers has_many :employees

So I have 2 models: Picture and Comment. Pictures have many Comments, but I''d like for users to be able to post Pictures in Comments, so Comments will have one Picture (possibly). This creates a kind of circular relationship it looks like, and the only way I could think of to implement this is with has_and_belongs_to_many. Am I right, or is there a better way to do this?

I''m working with three models: - Charge. has_many :budget_plans - BudgetPlan. belongs_to :charges, :rollups - Rollup. has_many :budget_plans This works out perfectly. A budget plan contains the ID of a charge and rollup and then there''s a 3rd attribute for hours. So working with data is no problem. My budget plan scaffold works nicely so I can select a charge, select a

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

Hello everyone, first post to the list and a relative newbie to Rails development. Done quite a bit of JSP, PHP, HTML, XML etc and thought I would kick the tires on Rails to see if it can speed up development for internal applications. Anyway, I am running into a problem that is just driving me crazy and everything I read on the net doesn''t seem to help. I was hoping someone here might

I have a simple CMS I''m creating, and the primary model is the "listing". A listing habtm (has_and_belongs_to_many) categories (up to two) - allowing the listing to print its categories and a category to print its listings. I also need subcategories, which are different from categories in two ways: a listing can have as many subcategories (from it''s two categories)

I''m a rails newb and have been Googling about this, but I''m still stumped. Not showing everything here, but basically it should be a pretty common setup so I''m sure others know what I''m doing wrong. - A meter can belong to many meter_groups - A meter_group can have many meters. - A user can ''subscribe'' to viewing a meter_group (Subscription)

hello, I''am new to ROR and I have a problem. I have to models "rights" and "roles" on a has_and_belongs_to_many relationship, through "roles_rights" table. When I try to add a new role although I put in my form fields for each right, a record is added to table roles but none to roles_rights. I am using Ruby 1.8.4 rails 1.0 mysql 5.0 here is my code:

Hi, I am trying to perform a query with ActiveRecord that I want to put into a Rails application later. For now I just wrote it within a plain old Ruby script for easier testing. I am working with an existing database so I had to map some foreign keys myself. As you can see from the models below, the database has a structure of Prospectlists <=habtm=> Contacts <=habtm=> Accounts

Trying to model a bunch of users that have friends that are other users. clearly a job for has_and_belongs_to_many, but the trick is, they have ratings for their friends. I have gone through the Rails Recipes book, and it seems like I''m trying to combine the self-referential many-to-many recipe (12) and the many to many relationships where the relationship itself has data recipe (16). So

Hi All, I think Im having a mental block here. For some reason I just cant get my head round relationships. What I have is the following. 4 tables 1) Hosts 2) Software 3) OperatingSystem 4) Company In my terms (which are most likely wrong) a company can have lots of hosts, a host has lots of software, a host has one operating system. So should my models have the following relations in them?

I have a class Player, and a class Game. Game has two HABTM relationships to the Player table through seperate relationship tables. class Game < ActiveRecord::Base has_and_belongs_to_many :players, :uniq => true has_and_belongs_to_many :victors, :class_name => ''Player'', :uniq => true end When I add Player A to players, and Player B to victors, and save the

Hi ! (See references at the end) I have a slight problem. Whenever I save one of my domain models, which contains an has_and_belongs_to_many relationship with another one, the relationships are doubled. My domain is a series of pictures, where each picture can be tagged with one or more words. So, a picture of my dog could be tagged "Jordy, Dog, Dog 2005", for example. In my

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