Displaying 20 results from an estimated 110 matches similar to: "Multiple HABTM relationships with self ???"
2005 Dec 19
2
Difficulty using correct moldel for the data in DB
Hi everyone,
I''ve tried posting the same question to the list last Friday but
somehow did not see it being posted..
I''ve just started with Rails and Ruby. I just started to play one of
those RPG and to get my feet wet I''m writing an app to keep track of
item fusions. So the scoop is that item can be fused with another
items to create a higher level item. The higher
2006 Jan 19
5
limits of has_and_belongs_to_many
I''m experimenting with Rails on the Recipes example first before I dive
into applying it to my intended application. I''m exploring which will be
more work: to rename all the primary id''s in the legacy database, or to
work around the fact that the primary id''s are not called ''id'' within
RoR instead.
I''ve been successful in using a
2005 Mar 01
0
has_and_belongs_to_many problem
I''m having a problem with a has_and_belongs_to_many (habtm)
association between two models with extra attributes. I''m writing a
comic book database, and each issue has many creators on it. Thing
is, some creators perform multiple duties. They may write one issue,
draw another, etc.
However, if I add a creator twice to an issue and try to delete it, it
removes both creators:
2006 Jan 19
0
Help with nested HABTM relationship
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
2007 Jan 03
3
Self-referential habtm with condition is broken
Here''s a simplistic model class.
class Person < ActiveRecord::Base
has_and_belongs_to_many :relatives,
:class_name => ''Person'', :join_table => ''relatives'',
:foreign_key => ''from_id'', :association_foreign_key => ''to_id''
has_and_belongs_to_many :brothers,
:class_name =>
2005 Oct 05
0
has_and_belongs_to_many on legacy DB
I am working with mapping ActiveRecord onto a legacy database. All is going
well (using set_table_name, set_primary_key, etc), but I can''t get my
many<=>many relationships to work.
My contrived example of the situation:
Student has_and_belongs_to_many Teachers. This is mapped via table
student2teacher where the foreign keys are studentId and teacherId. The
primary key in Student
2007 Nov 30
0
cross sell products - Options_from_collection_select ?
Hi
I have collected some code for cross sell products on this website.
CREATE TABLE products (
id INT NOT NULL AUTO_INCREMENT,
name varchar(255) NOT NULL,
PRIMARY KEY (id)
);
INSERT INTO products VALUES (1, ''alpha'');
INSERT INTO products VALUES (2, ''beta'');
INSERT INTO products VALUES (3, ''gamma'');
CREATE TABLE cross_sells (
product_id
2006 Mar 25
0
Self-Referential Many-To-Many relationships where the relationship itself has data.
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
2007 Oct 22
1
self-referential habtm: why are my keys null?
I''m trying to set up a directional self-referential HABTM to represent
an arbitrary semi-hierarchical structure; it works for any data
prepopulated into the db, but when I try to create a new relationship,
I just get NULLs in both key columns (or 0''s if I turn on the no-null
constraint).
Here are the migrations:
class CreateNodes < ActiveRecord::Migration
def self.up
2006 Jul 23
0
Schema design with edge class
I have a situation similar to that described on
http://wiki.rubyonrails.org/rails/pages/HowToUseManyToManyAgainstASingleTable
On that page, someone made the comment:
One might argue also that this is contrived, and you should create a
real Edge class. This way when you finally realise ?whoops, I need to
colour the edges of the graph?, you have somewhere to store that
property.
Which
2005 Dec 18
0
Difficulty with creatating a model
Hi everyone,
I''ve just started with Rails and Ruby. I just started to play one of
those RPG and to get my feet wet I''m writing an app to keep track of
item fusions. So the scoop is that item can be fused with another
items to create a higher level item. The higher level items can be
fused to create even higher level items ... etc.
I''m using MySQL to store the data.
2006 May 16
4
Problems with multiple ''id'' columns in a join_table
I have a problem declaring a relationship through a join_table ; the SQL
generated by ActiveRecord is correct, but there are two columns called
''id'', and the final object gets the ''wrong'' column ...
Here''s a more detailed description of the data, code, and problem :-
There''s a People table, with id, name, and a few things.
Also a
2006 Jul 12
0
two-way dictionary
Hi!
I''m working on a multi-language idioms mapping application in which
an expression object has a habtm relation with its own class.
I thus created a table ''expressions_dictionary'' and would go about by
declaring something like:
has_and_belongs_to_many :peers,
:class_name => "Expression",
:join_table
2006 May 02
0
Self-referential MtoM implementation
ok, guys i have followed the self referential recipe from the book it
works perfect but now i have some doubts, at the end the model are
modified to force the user beign added as a friend that add too who are
adding him so how i can make that the full relationship doesn?t be
complete until the friend beign added approves it(talking in the
implementation of the code of course)?
by the way,
2006 Apr 01
3
has_and_belongs_to_many construction
Hi there,
I''ve got a table construction like this:
presentation contactstate
Hilton new
Mc Donalds emailed
etc. called
visited
etc.
Now i''ve created an join table presentationcontactstate with extra
fields like comment and date time. so i know for example when i called a
specific presentation.
Now
2006 Apr 03
1
has_many :trough with 2x the same table
I have a site where Users can become Friends with other Users. I used to do this with a habtm, but of course I want to stay up-to-date and convert this to a has_many :trough. Unfortunately I can''t get it to work.. the documentation on this feature is a bit sparse at the moment.
This is my old habtm:
has_and_belongs_to_many :friends, :join_table => ''user_friends'',
2006 Apr 27
0
last stupid question today
(well, from me anyway. I promise)
Trying to follow the "Self-referential Many-to-Many Relationships" recipe
from the Rails Recipes book.
This is what I''m doing: Tasks can have a predecessor relationship with each
other. My Task class has this:
has_and_belongs_to_many :predecessors,
:class_name => "Task",
:join_table => "predecessor",
2006 Jan 03
0
habtm and insert_sql
Briefly, I want to create an :insert_sql attribute for
a has_and_belongs_to_many relationship, and then add items to that
relationship using push_with_attributes. Is that possible?
Less briefly:
I have a legacy postgresql database where one of the join tables has an
ID column, so I had to set up the association with a custom :finder_sql
attribute, as follows:
class Topic <
2006 Jan 06
0
bug rails activerecord association join
hi,
I found a bug in ActiveRecord association SQL INNER JOIN codes. in
has_many, has_one, habtm and belongs_to queries the foreign key is
determined from the table name of reflection and self. but that''s
worng because if you use a global prefix or suffix for your tables the
foreign keys will be in format of PREFIX_CLASSNAME_SUFFIX_id which is
wrong, because it breaks the advantage of
2006 Jan 06
2
Re: Some advice on DB modeling
I have more or less the same problem. I''m trying to build a system where
users can enter their friends. But the solutions seems not to work for me.
I used same sql:
CREATE TABLE `friends` (
`user_id` int(11) NOT NULL default ''0'',
`friend_id` int(11) NOT NULL default ''0'',
KEY `user_id` (`user_id`),
KEY `friend_id` (`friend_id`),