Simple select question

Rails
1

Currently i’m getting all the stories that belong to a given article,
and listing them, with

for story in @article.story

the usual sort of thing, right?

I want to add a condition, that only selects stories where the
‘complete’ field is equal to 1. So, it’s like saying

for story in Story.find(:all, :conditions => [“article_id = ? and
complete = ?”, @article, 1])

but in the view. There must be a simple way to do this but i can’t find
it - can someone help please?

2

On Sep 3, 2007, at 10:03 AM, Max W. wrote:

for story in Story.find(:all, :conditions => [“article_id = ? and
complete = ?”, @article, 1])

but in the view. There must be a simple way to do this but i can’t
find
it - can someone help please?

Posted via http://www.ruby-forum.com/.

in Model:

class Article
has_many :completed_stories, :conditions => [ ‘complete = ?’, true ]
end

(If you’re declaring the complete column to be a boolean, then this
is better than using 1 even though the SQL will be exactly the same
as it reveals the meaning more.)

in view:

for story in @article.completed_stories

Alternatively, you could set a @completed_stories instance variable
in the controller and just have “for story in @completed_stories” in
the view.

You’ll find that the system is more easily changed later if you push
this kind of logic into the model wherever practical.

-Rob

Rob B. http://agileconsultingllc.com
[email protected]

3

Rob B. wrote:

in Model:

class Article
has_many :completed_stories, :conditions => [ ‘complete = ?’, true ]
end

Ah - that’s great thanks. I ended up doing something similar, making a
method in the article model:

def completed_stories
Story.find(:all, :conditions => [“article_id = ? and complete = ?”,
self, 1])
end

but your suggested way is much nicer. Cheers!

4

Max W. wrote:

Rob B. wrote:

in Model:

class Article
has_many :completed_stories, :conditions => [ ‘complete = ?’, true ]
end

Ah - that’s great thanks. I ended up doing something similar, making a
method in the article model:

def completed_stories
Story.find(:all, :conditions => [“article_id = ? and complete = ?”,
self, 1])
end

but your suggested way is much nicer. Cheers!

Actually there’s an amendment needed (in my case at least), in case
anyone else is trying to do this: you need to specify the class that
:completed_stories is coming from:

has_many :completed_stories,
:class_name => “Story”,
:conditions => [ ‘complete = ?’, true ]

5

You can use Max W. suggestion if you always want the condition
with the SQL or you could do as you did with defining a function for it!
:slight_smile:

6

There are a couple ways to do it that I would suggest.

Adding another association works but it’s a bit cumbersome. Luckily,
rails provides these lovely association extensions you can use to
define new methods on the association:

class Article < ActiveRecord::Base

has_many :stories do
def completed
find(:all, :conditions => “complete = 1”)
end
end

This allows you to do:

@article.stories.completed

rather than @article.completed_stories

Alternatively, once you’re in the view, you can always use select to
filter the array:

@article.stories.select{ |story| story.complete == 1}.each do |
story| ;; end

Not the cleanest, but if you’re already using @article.stories
elsewhere, it won’t hit the database again.

Rein

On Sep 3, 11:19 am, Rob B. [email protected]

7

class Article < ActiveRecord::Base

has_many :stories do
def completed
find(:all, :conditions => “complete = 1”)
end
end

Alternatively, once you’re in the view, you can always use select to
filter the array:

@article.stories.select{ |story| story.complete == 1}.each do |
story| ;; end

Not the cleanest, but if you’re already using @article.stories
elsewhere, it won’t hit the database again.

Both good tips, thanks Rein!