Displaying 20 results from an estimated 1000 matches similar to: "table that have many-to-may relationship to itself"
2006 Aug 15
2
How to access attribute in a self-referential many-to-many relationship
Hello List,
I created a self-referential many-to-many relationship (as described
in the book Rails recipe #18), where I have a model that has
many-to-many relationships with itself. In this case, it''s person who
can become friends. The join table looks like this:
mysql> select * from friends_people;
+-----------+-----------+-----------+
| person_id | friend_id | confirmed |
2006 May 28
3
Association of table to itself
I''m curious what would be the best way to represent people and whether the
person has someone marked as their friend. Here are my thoughts so far:
People table
- id
- name
Relationships table
- person_id
- friend_id
Now my problem is I don''t know how to set up these associations (if this is
even correct). Friend_id would be an id to someone else from the people
table.
2006 Aug 02
2
Self-Referential has_many :through
Hello all.
I am trying to create a self-referential has_many :through. I used the
following site as a guide
http://blog.hasmanythrough.com/articles/2006/04/21/self-referential-through
but it still doesn''t appear to be working. I have two models. Person and
Relationship. A person has many contacts (Which is another person)
through relationships
class Person < ActiveRecord::Base
2006 Feb 21
7
Self-referencial habtm relationship
Heyo!
I am setting up a self-referencial habtm relationship with the users
of my app. I am using Chad Fowler''s "Rails Recipes" to get me started,
and everything works great with the join table "people_friends". I add
friends by doing somebody.friends << somebodyelse. However, with my
app, there is an approval process so my join table has columns
person_id,
2006 May 28
7
Self-referential has_many :through relationship
Hi,
I have a self-referential has_many :through relationship setup to
track relationships between users. Basically relationships are
modeled as a join table with an extra column ''relation''.
create table relationships (
user_id integer unsigned not null,
friend_id integer unsigned not null,
relation char(1) not null,
)
--- relations ---
f = friend
r = request to
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 Mar 31
6
Adding objects to a :through association
So I''m one of those nasty people building a self-referential
habtm-like Association using the funky new :through stuff. This is
about users having friends, so here''s my user.rb:
class User < ActiveRecord::Base
has_many :friendships, :foreign_key => ''user_id''
has_many :friends, :through => :friendships, :source => :friend
end
And here''s
2006 Nov 02
4
Still Having Problems With :through When Going To Same Table... Help... please :-(
I am having a problem with doing a :through that goes back to the same table.
The following are my two classes:
>>>>>
class User < ActiveRecord::Base
has_many :spanks
has_many :spanked, :through => :spanks, :source => :spanked_user
has_many :was_spanked_by, :through => :spanks, :source => :user
end
class Spank < ActiveRecord::Base
belongs_to :spanker,
2008 Aug 29
3
Many to Many Relationship with One Model
Hey everyone,
I''m working on allow users to follow other users in my app so they can
receive updates to what all their friends are doing (like Facebook/
Twitter). I''m wondering on how the relationship would be for the
model. Sounds like a HABTM type of association, but how would I go
about doing it for only one model?
Thanks,
Tony
2006 Jan 24
3
Merging two heavily referenced records into one
Here''s the situation: I have a "people" table whose "id" column serves
as a foreign key to several other tables (authorships, editorships,
members, users, etc.). Every now and then I will find two distinct
records in the "people" table that represent the same human being. They
generally differ by small differences in spelling but should really be
the
2006 Jul 17
14
REST Relationship Models
I''m trying to figure out an elegant way to do this:
I have the following three tables:
people, employer, employees
And consequently the following three models:
class Person < ActiveRecord::Base
end
class Employer < ActiveRecord::Base
has_many :employees
end
class Employee < ActiveRecord::Base
belongs_to :person
belongs_to :employer
end
I want to be able to say:
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`),
2009 Feb 27
4
Optimize for loop / find last record for each person
I want to find the last record for each person_id in a data frame
(from a SQL database) ordered by date. Is there a better way than
this for loop?
for (i in 2:length(history[,1])) {
if (history[i, "person_id"] == history[i - 1, "person_id"])
history[i, "order"] = history[i - 1, "order"] + 1 # same person
else
history[i,
2006 Aug 02
2
many-to-one relationship, do I need a second table?
Ok, to keep things short. Im wondering if I need a secondary
relationship table to handle my many-to-one relationships. Here is an
example of what I''ve written down. For instance say I want to find all
of the people in a given location.
class Location < AR:Base
has_many :people
end
class Person < AR:Base
belongs_to :location
end
My SQL tables look like:
CREATE TABLE
2007 May 16
5
drop a letter
hello,
how can I do to drop C from this character "C325" ?
_____________________________________________________________________________
[[alternative HTML version deleted]]
2006 Jan 09
3
Design Question
I am sure some of you can give me an insight into this. This is more
towards the database design for the scenario below:
Say for example,
I have a person table and this person can have different address types.
One could be Home and the other could be say Office.
Should be model this
Table people
id
fname
lname
Table addresses
id
person_id
addr1
addr2
....
or
Table people
id
fname
lname
2006 Mar 15
1
Through method problems with custom foreign_keys
A person has a many company_branches and
A company_branch has many people.
This join is represented using a "contacts" table.
I am using a legacy schema so i am forced into using non-standard rails
primary keys. I am using the new through relationship in rails 1.1.
p=Person.find(1)
b=p.company_branches # gives this error:
ActiveRecord::StatementInvalid: OCIError: ORA-00904:
2006 May 26
3
Breakdowns in has_many abstraction
I discovered an interesting aspect of has_many behavior that I''m
struggling to work around. I''m not sure if I''m doing something wrong,
or if it''s a legitimate bug, or if it''s an inherent part of Rails that
I just have to learn to deal with.
It boils down to these two problems:
- changes in collection objects (i.e. models that belong_to a
container
2006 Apr 17
1
database design Q
I am in the middle of setting up mysql database for my RoR application.
and here is some questions in my mind hope you can help.
1. this is a photoblog story telling like system, where people can creat
their own groups
the database tables are: people, groups, articls, pictures
People to Groups are many-to-many relationships
People to Articles are one-to-many
Group to Articles are one-to-many
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