Anyone know how to add an element to a object instance variable and not overwrite it?

Rails
1

Heres the code Im using:
for admirer in @admirers
@avatars =||(??) Avatar.find(:all, :conditions => { :user_id =>
admirer.admirer_id, :thumbnail => ‘tiny’ }) end

I want to add a new Avatar object to @avatars for each admirer_id and
Im confused on the syntax to do this. Does this make sense at all?
Anyone know how to do this? Please help if you have any ideas, Ive
been looking all over online to try and figure this out but to no
avail. Thanks. :wink:

2

Avatar.find(:all …).collect{|avatar| @avatars << avatar}

should work

3

On Dec 13, 2007, at 10:22 AM, Dave L. wrote:

avail. Thanks. :wink:
A way to append the contents of an array to another is to use +=, this
way:

@avatars += Avatar.find(…)

On the other hand that query looks non-idiomatic, and the column
admirer.admirer_id a bit suspicious, since it would normally be
admirer.id (or admirer.admired_id if you have there the ID of the who
admirer admires).

Depending of the details you’d end up writing something like that
looks like this:

@avatars += admirer.avatars.find_all_by_thumbnail(‘tiny’)

– fxn

4

On Dec 13, 2007, at 12:49 PM, Dave L. wrote:

admired the profile. Do you have any ideas why I would be getting
this error. Thanks for your time, Dave

I would expect a user has_many :admirers, and has_many :avatars. On
the other hand an avatar belongs_to :user. With those relationships,
if the entry point is an avatar you’d do this:

@admirers = avatar.user.admirers

Perhaps you could show an avatar but directly put the user id in the
associated link… Does that make sense?

– fxn

5

Thanks so much for the input. Ive been tinkering with the code and am
getting this error:
Unknown column ‘avatars.admirer_id’ in ‘where clause’: SELECT * FROM
avatars WHERE (avatars.admirer_id = 11)

The admirer model has a ‘has_one :avatar’ relationship. Is there some
other kind of relationship i need to define. To clarify the
admirer_id, I also store who the admirer admires as user_id. My
ultimate goal is to make a profile where someone can click “admire
this person” and then that profile displays all the people who have
admired the profile. Do you have any ideas why I would be getting
this error. Thanks for your time, Dave

6

On Dec 15, 2007, at 12:34 AM, Dave L. wrote:

Ive been working on this for the past couple days but no go. The
biggest confusion stems from the fact that I want to find all the
admirer_id’s in the admirer table by matching them to the current
profile through the user_id. So lets say the user_id is 4, then I
search through the admirers table and find all the admirer_id’s that
match a user_id of 4. Then I want to take these admirer id’s and
create an @avatar object containing all the avatars that have their
user_id column match the admirer_id.

It would be useful to know the actual tables and column names, class
definitions, and model relationships you have written. Please send
this with plain code, not English. Strip everything that it is not
relevant.

– fxn

7

Ive been working on this for the past couple days but no go. The
biggest confusion stems from the fact that I want to find all the
admirer_id’s in the admirer table by matching them to the current
profile through the user_id. So lets say the user_id is 4, then I
search through the admirers table and find all the admirer_id’s that
match a user_id of 4. Then I want to take these admirer id’s and
create an @avatar object containing all the avatars that have their
user_id column match the admirer_id. I think there must be some way
to do this through creating indexes, but Im new to the database
relationships so its not so straightforward. The way I had it set up
above doesnt look scalable at all:
for admirer in @admirers
@avatars =||(??) Avatar.find(:all, :conditions => { :user_id =>
admirer.admirer_id, :thumbnail => ‘tiny’ }) end

because this is going to have to search the entire admirers table and
then cross reference the entire avatar table, which canget very
expensive with a lot of users. Do you have any ideas about how to
implement indexes in this situation. Thanks for your help. Youve
helped me a lot already.

8

Here are the relevant tables and classes:

Admirers Table : id, user_id, admirer_id (the admirer_id is the one
that needs to be displayed by creating an avatar object with the
corresponding user_id)

class Admirer < ActiveRecord::Base
belongs_to :user
end

Avatars Table: id, user_id, content_type, thumbnail, size, width,
height (uses attachment_fu)
class Avatar < ActiveRecord::Base
belongs_to :user
end

Users Table: id, screen_name, email, password, gender
class User < ActiveRecord::Base
has_one :photo
has_many :avatar
has_many :admirer
end

thanks so much!

9

On Dec 15, 2007, at 1:24 AM, Dave L. wrote:

class Avatar < ActiveRecord::Base
belongs_to :user
end

Users Table: id, screen_name, email, password, gender
class User < ActiveRecord::Base
has_one :photo
has_many :avatar
has_many :admirer

You put those two in plural, right?

end

The problem you are facing comes from the fact that there’s no link
between admirers and avatars, yet you want to join them.

This in turn is consequence of what seems a not yet rounded model: to
admire and being admired is a relationship between users. That’s a
hands_and_belongs_to_many linking users to users, you need to link
them both ways.

The admirer’s table would have as columns: “admirer_id”, “admired_id”,
and NO column “id” (create_table :admirers, :id => false do |t| …).

In the User model you have

has_and_belongs_to_many :admirers, …, :join_table => ‘admirers’
has_and_belongs_to_many :admireds, …, :join_table => ‘admirers’

Check the API for the options in the ellipsis, Google for “self-
referential has_and_belongs_to_many” as well.

Then you have a link from users to avatars going through admirers,
because

user.admirers

is a collection of users, and they have avatars.

– fxn