<http://wiki.rubyonrails.org/rails/pages/ThroughAssociations> suggests, essentially, using "baz" while I believe that I''ve seen sources suggesting "foos_bars" and, I believe, "foo_bars". In particular, on this list, joining tables "foos" and "bars" with a many-to-many, "foos_bars" was recommended for the join table. Why? Does it matter? What''s correct? thank you, Thufir --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Check out this ActiveRecord tutorial: http://railsenvy.com/tags/activerecord%20tutorial%20video Skip to about 2/3 of the way in and there is a section on many-to-many relationships that explains it quite well. On Dec 14, 12:23 pm, Thufir <hawat.thu...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> <http://wiki.rubyonrails.org/rails/pages/ThroughAssociations> suggests, > essentially, using "baz" while I believe that I''ve seen sources > suggesting "foos_bars" and, I believe, "foo_bars". In particular, on > this list, joining tables "foos" and "bars" with a many-to-many, > "foos_bars" was recommended for the join table. > > Why? Does it matter? What''s correct? > > thank you, > > Thufir--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
I always used foos_bars as a join table for a habtm association. I don''t get the ''baz'' but i think it references when you have a many to many relationship through something other than a join table? On Dec 14, 2:23 pm, Thufir <hawat.thu...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> <http://wiki.rubyonrails.org/rails/pages/ThroughAssociations> suggests, > essentially, using "baz" while I believe that I''ve seen sources > suggesting "foos_bars" and, I believe, "foo_bars". In particular, on > this list, joining tables "foos" and "bars" with a many-to-many, > "foos_bars" was recommended for the join table. > > Why? Does it matter? What''s correct? > > thank you, > > Thufir--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
with habtm, you have to use foos_bars. With has many :through, the join table in a model in its own right and so you can call it anything you want. When possible you should strive to find a ''proper'' name for the join model. For example if your app was a forum type application, where users could subscribe to topics then a good name for the join model between users and topics would be ''subscription'' Fred On Dec 14, 8:15 pm, Charles <rowe.char...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I always used foos_bars as a join table for a habtm association. > I don''t get the ''baz'' but i think it references when you have a many > to many relationship through something other than a join table? > > On Dec 14, 2:23 pm, Thufir <hawat.thu...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > <http://wiki.rubyonrails.org/rails/pages/ThroughAssociations> suggests, > > essentially, using "baz" while I believe that I''ve seen sources > > suggesting "foos_bars" and, I believe, "foo_bars". In particular, on > > this list, joining tables "foos" and "bars" with a many-to-many, > > "foos_bars" was recommended for the join table. > > > Why? Does it matter? What''s correct? > > > thank you, > > > Thufir--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On Dec 14, 12:15 pm, Charles <rowe.char...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I always used foos_bars as a join table for a habtm association. > I don''t get the ''baz'' but i think it references when you have a many > to many relationship through something other than a join table?[...] I don''t have it in front of me, but in the "rails recipes" book, one of the recipes is for a habtm relationship. They have three tables, foos, bars, and baz. They don''t use "foos_bars" to my recollection. That is, the name for the join table is unrelated to the name for either table. However, that''s based on my recollection that it''s a habtm relationship, but I think so. -Thufir --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
> I don''t have it in front of me, but in the "rails recipes" book, one > of the recipes is for a habtm relationship. They have three tables, > foos, bars, and baz. They don''t use "foos_bars" to my recollection. > That is, the name for the join table is unrelated to the name for > either table. However, that''s based on my recollection that it''s a > habtm relationship, but I think so. >from the api documentation: "Unless the join table is explicitly specified as an option, it is guessed using the lexical order of the class names. So a join between Developer and Project will give the default join table name of developers_project" --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
This is my take on it:
OLD WAY - has_and_belongs_to_many :my_model
This is an out of date technique to set up the many-to-many table. A
major limitation to this method is that you cannot have any more fields
in the table then the 2 joining fields, and the join table does not use
a primary field key called id. You cant sort joined fields very
easily with this method.
This technique is very easy to set up. The table name is the plural
names of the 2 joining tables, in alphabetical order, separated by an
underscore. Table C and B would be BS_CS. The only 2 fields in the join
table would be b_id and c_id.
NEW WAY - has_many :through
This technique allows the join table to have as many fields as you
want. You need a model, for the joining, to make this work. You can just
generate a model. But if you need more fields, you can scaffold. The
join table also gets the primary key field (id) that is automatically
generated in most cases.
The joining table can be named what ever you want. The current trend
is to use a table name that just has one word, and usually ends in
-ship, -tion, or -ment. There can be endless hours of debate over the
name of the joining table.
You will need to have the 2 joining tables foreign key fields in
this table, like the fashion <tablename>_id, that are not pluralized.
If you wanted to join table A and table B, an example of the joining
table could be:
TABLES
A
id (integer, primary key)
name (string)
B
id (integer, primary key)
name (string)
AB (many table for joining tables A and B)
id (integer, primary key)
a_id (integer)
b_id (integer)
(more fields)
The MODELS
A
has_many :ABs
has_many :Bs :through => :ABs
AB
belongs_to :A
belongs_to :B
B
has_many :ABs
has_many :As :through => :ABs
SOME OPTIONS
has_many :mytable, :foreign_key =>
''myfield_id'',
:class_name =>
''myclassname'',
:dependent => :destroy
--
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On 12/14/07, gemblon (t.b.) <rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:> > This is my take on it: > > OLD WAY - has_and_belongs_to_many :my_model > > This is an out of date technique to set up the many-to-many table. A > major limitation to this method is that you cannot have any more fields > in the table then the 2 joining fields, and the join table does not use > a primary field key called ''id''. You can''t sort joined fields very > easily with this method.This makes it sound like HABTM is obsolete. It isn''t if you don''t need to have attributes on the association, I think it serves perfectly way.> This technique is very easy to set up. The table name is the plural > names of the 2 joining tables, in alphabetical order, separated by an > underscore. Table C and B would be BS_CS. The only 2 fields in the join > table would be b_id and c_id.And if the too records were foo and bar, the join table would be bars_foos, not foos_bars as has been mistakenly said at least once in this thread. On the other hand, the link in the original post was to a description of :has_many :through and I think that the OP was confused between examples of HABTM and HM T. -- Rick DeNatale My blog on Ruby http://talklikeaduck.denhaven2.com/ --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On Tue, 18 Dec 2007 08:59:33 -0500, Rick DeNatale wrote:> And if the too records were foo and bar, the join table would be > bars_foos, not foos_bars as has been mistakenly said at least once in > this thread.What''s the distinction between foos_bars and bars_foos please? A many-to- many isn''t "directional", is it? thanks, Thufir --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On 19 Dec 2007, at 08:54, Thufir wrote:> > On Tue, 18 Dec 2007 08:59:33 -0500, Rick DeNatale wrote: > > >> And if the too records were foo and bar, the join table would be >> bars_foos, not foos_bars as has been mistakenly said at least once in >> this thread. > > What''s the distinction between foos_bars and bars_foos please? A > many-to- > many isn''t "directional", is it? >No, but you''ve got to pick something and by default hatbm would pick bars_foos (My mistake for saying foos_bars earlier - Time to brush up on my alphabet :-) ) Fred> > > > thanks, > > Thufir > > > >--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On Tue, 18 Dec 2007 08:59:33 -0500, Rick DeNatale wrote:> On the other hand, the link in the original post was to a description of > :has_many :through and I think that the OP was confused between > examples of HABTM and HM T.Yeh, a bit. Ooops :) -Thufir --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On Wed, 19 Dec 2007 09:04:32 +0000, Frederick Cheung wrote:> No, but you''ve got to pick something and by default hatbm would pick > bars_foos (My mistake for saying foos_bars earlier - Time to brush up on > my alphabet )Oh, because that''s alphabetically sorted? -Thufir --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---