Listing of Category error

rubyonrails-talk
1

Im trying to see posts index page, In tat im showing category list, im using collect method it show error..

ActiveRecord::StatementInvalid in Posts#index Showing app/views/posts/index.html.erb where line #19 raised:

Mysql::Error: Unknown column 'categories_posts.category_id' in 'on clause': SELECT `categories`.* FROM `categories` INNER JOIN `categories_posts` ON `categories`.id = `categories_posts`.category_id WHERE ((`categories_posts`.post_id = 1))

Extracted source (around line #19):

16: <td><%= post.created_at.strftime('%m/%d/%y %I:%m %p') %></td> 17: <td><%= h(post.title) %></td> 18: <td><%= h(post.author.display_name) if post.author %></td> 19: <td><%= post.categories.collect {|cat| [cat.name] }.join(",") %> 20: <td><%= h(post.status) %></td> 21: <td><%= post.comments_count %>

pls help me, im new to RoR..??

2

You must declare a has_many :categories in the Post model and a belongs_to :post in the Category model (if the category table has a post_id column, if not keep reading). If you don't do that, you need to create a categories_posts table with two columns: category_id and a post_id.

Regards.

Franco Catena.

3

Hi,

Im new to Ror, i want to do some userful website can u tell me ur advice and wat steps i should to take basically in Ruby on Rails..?? then im trying to understand tat ( models, controller, action ) it confusssed.. pls help me..

haneef5k@gmail.com

4

You can read the Agile Web Development With Rails (http:// www.pragprog.com/titles/rails3), is a very good book. It explains step by step the framework and a very common (but usefull) workflow.

Regards.

Franco Catena.