Why can't I 'count' the results from a model 'find'?

rubyonrails-talk
1

Hi,

I'm running the following code in my show() method:

        @articles = Article.find(:all, :conditions => ["issue_id = ?", @issue.id], :order => '`column`,position')

        if (params[:article_id])           @article_id = params[:article_id].to_i           c = 0           total = @articles.count           while (c < total)             if @article_id == @articles[c].id               if c == 0                 @article_prev = @articles.last.id               else                 @article_prev = @articles[(c-1)].id               end               if ((c+1) == total)                 @article_next = @articles.first.id               else                 @article_next = @articles[(c+1)].id               end             end           end         else           @article_id = 0           @article_main = @articles.first.id           @article_prev = @articles.last.id           @article_next = @articles[1].id         end

Now to be honest this code is already a bit odd for me but I have no idea how else to approach this in Ruby on Rails. So I've attempted to do it PHP-style. But I'm being told that I can't do @articles.count

Why? I have a user model and a user has a one to many relationship with articles so I know that: @user.articles.count works. Hence I'm guessing there's something big I'm missing here.

So, how am I going to do this? How do I easily cycle through my list of articles and get the previous and next ones?

Any help greatly appreciated. I've been going back and forth over my books and forums but I can't seem to formulate the question to be able to ask it.

2

Hi,

I'm running the following code in my show() method:

       @articles = Article.find(:all, :conditions => ["issue_id = ?", @issue.id], :order => '`column`,position')

       if (params[:article_id])          @article_id = params[:article_id].to_i          c = 0          total = @articles.count

....

       end

Now to be honest this code is already a bit odd for me but I have no idea how else to approach this in Ruby on Rails. So I've attempted to do it PHP-style. But I'm being told that I can't do @articles.count

Why? I have a user model and a user has a one to many relationship with articles so I know that: @user.articles.count works. Hence I'm guessing there's something big I'm missing here.

So, how am I going to do this? How do I easily cycle through my list of articles and get the previous and next ones?

@user.articles.count is Rails magic. It's not actually fetching everything and then counting it up, it's looking at the associations and building a "SELECT COUNT...."

@articles above is an array. Try @articles.size.

-philip

3

@user.articles.count is Rails magic. It's not actually fetching
everything and then counting it up, it's looking at the associations
and building a "SELECT COUNT...."

To be quite precise, @user.articles is not an array, it's an association proxy.

Fred

4

Thanks both of you.

I've got it working now. :slight_smile: