I need a one-liner to generate a has_and_belongs_to_many join table or else I will go back to Django for its simpler many-to-many constructs.
rails 3 generate model article_tags [..]
Models
# article.rb
has_many :articles_tags
has_many :tags, :through => :articles_tags
# tag.rb
has_many :articles_tags
has_many :articles, :through => :articles_tags
# article_tag.rb
belongs_to :tag
belongs_to :article
Ohh wait haha, I think this might do the trick:
rails g model articles_tags article:references tag:references --no-id --no-timestamps
I wonder if there is anyway to suppress the model file's creation (article_tags.rb) so that I can just use the standard has_and_belongs_to_many syntax without having to specify a :through param? I'm looking for the ultimate one-liner: Tip of the hat to anyone who can improve the above one-liner to enable only the use of has_and_belongs_to_many syntax without a join model! Else, I'm going back to Django, with it's built-in ManyToManyFields.
It sounds like you're looking for the standard has_and_belongs_to_many:
# article.rb
has_and_belongs_to_many :tags
# tag.rb
has_and_belongs_to_many :articles
Your join table would be called articles_tags, and need just contain two columns, article_id and tag_id (no id column needed since it isn't a model).
This is in the Rails Guide to Associations. I highly recommend becoming familiar with the Rails Guides.
It's almost too simple for a generator. All you need are two empty model classes and the join table, which would be defined in a migration like so:
def self.up
create_table :articles_tags, :id => false do |t|
t.integer :article_id
t.integer :tag_id
end
end
def self.down
drop_table :articles_tags
end
Don't know if this is still of interest after so much time, but I think you can take a look at https://github.com/zealot128/ruby-habtm-generator: it's a Rails generator that generates the correct migration for the HABTM table.
Using generate will create two indexes
Check this answer https://stackoverflow.com/a/9825571/643500
