has-and-belongs-to-many

I have 2 models: class User < ActiveRecord::Base has_and_belongs_to_many :groups end class Group < ActiveRecord::Base has_and_belongs_to_many :users end I want to make a scope (that's important - for efficiency and for ability to chain scopes) that returns Users that doesn't belong to ANY Groups. After many tries, I failed in doing a method instead of scope, which makes collect on User.all which is ugly and.. not right. Any help? And maybe for 2nd question: I managed to make a scope that returns Users who belongs to any of given groups (given as an array of id's). scope :in_groups, lambda { |g

Tables restaurants cuisines cuisines_restaurants Both restaurant and cuisine model are set up to HABTM each other. I'm trying to get a paginated list of restaurants where Cuisine.name = 'italian' (example), but keep getting this error: 1054: Unknown column 'Cuisine.name' in 'where clause' Actual query it's building: SELECT `Restaurant`.`id`, `Restaurant`.`type` ..... `Restaurant`.`modified`, `Restaurant`.`user_id`, `User`.`display_name`, `User`.`username`, `User`.`id`, `City`.`id`,`City`.`lat` ..... FROM `restaurants` AS `Restaurant` LEFT JOIN `users` AS `User` ON (`Restaurant`.`user_id` =

Is it true that HABTM relationships do not support the :dependent option? class Person < ActiveRecord::Base has_and_belongs_to_many :posts, :dependent => :destroy end I am trying rails edge. Yep, It doesn't support it. See the docs . Generally habtm is meant only for very very simple cases and if you start needing more complex things you should switch to has_many :through . If you want to keep to the simple has_and_belongs_to_many association, you could add this: class Person < ActiveRecord::Base has_and_belongs_to_many :posts before_destroy { posts.clear } end Which will clear the join table

Is there anything explicitly wrong with using has_and_belongs_to_many associations in rails instead of has_many :through? I'm aware of these articles describing differences and work arounds, but they are from 2006. From things I've read on SO, it seems like people think that habtm is old and clunky, but what if a simple many to many join with no model necessary is what you're looking for? Thoughts? has_and_belongs_to_many is meant for simple many-to-many relationships. has_many :through, on the other hand, is meant for indirect one-to-many relationships, or many-to-many relationships with

I have setup this HABTM relationship in the past and its worked before....Now it isnt and I'm at my wits end trying to figure out whats wrong. I've looking through the rails guides all day and cant seem to figure out what I'm doing wrong, so help would really be appreciated. I have 2 models connected through a join model and I'm trying to find records based an attribute of the associated model. Event.rb has_and_belongs_to_many :interests Interest.rb has_and_belongs_to_many :events and a join table migration that was created like create_table 'events_interests', :id => false do |t| t.column

I have two models User and Movie.. Where those are associated with UsersWatchlist.. public $hasAndBelongsToMany = array('User' => array( 'className' => 'User', 'joinTable' => 'users_watchlists', 'foreignKey' => 'movie_id', 'associationForeignKey' => 'user_id', 'unique' => 'keepExisting', 'conditions' => '', 'fields' => '', 'order' => '', 'limit' => '', 'offset' => '', 'finderQuery' => '', 'deleteQuery' => '', 'insertQuery' => '' )) public $hasAndBelongsToMany = array( 'Movie' => array( 'className' => 'Movie', 'joinTable' => 'users_watchlists', 'foreignKey' => 'user_id', 'associationForeignKey'

Given the following class User < ActiveRecord::Base has_and_belongs_to_many :companies end class Company < ActiveRecord::Base has_and_belongs_to_many :users end how do you define factories for companies and users including the bidirectional association? Here's my attempt Factory.define :company do |f| f.users{ |users| [users.association :company]} end Factory.define :user do |f| f.companies{ |companies| [companies.association :user]} end now I try Factory :user Perhaps unsurprisingly this results in an infinite loop as the factories recursively use each other to define themselves. More

Spent all day on Google, but can't find an answer. :\ I have a HABTM relationship between Users and Core_Values. class CoreValue < ActiveRecord::Base has_and_belongs_to_many :users class User < ActiveRecord::Base has_and_belongs_to_many :core_values In my controller, I need to do two separate things: If a CoreValue does not exist, create a new one and associate it with a given user id, and Assuming I know a particular CoreValue does exist already, create the association without creating any new CoreValues or Users For # 1, I've got this to work: User.find(current_user.id).core_values.create({