Noob question: Creating model associations

rubyonrails-talk
1

I’m trying to create a simple blog app without scaffolding, and I’m having problems with associations.

I’m relatively new to this, and I would love some help. I’m sorry for bugging you with such a newbie question, but I couldn’t find a tutorial about this.

I made my models like this:

model g User username password

model g Admin

model g Poster

model g Post title content

then, I set the associations like this:

User

has_many :admins

has_many :users

Poster

belongs_to :User

Post

has_many :posts

belongs_to :Poster

Admin

has_many: users

then, when I go to the rails console, I cant make a post that belongs to poster, or a post that belongs to poster…

User.create(:name => “joe”)

usr = User.last

usr.Poster.create() ---- returns an error

What am I doing wrong here?

2

I'm trying to create a simple blog app without scaffolding, and I'm having problems with associations.

I'm relatively new to this, and I would love some help. I'm sorry for bugging you with such a newbie question, but I couldn't find a tutorial about this.

Have a look at the Rails Guide on ActiveRecord Associations. It should help.

I made my models like this: model g User username password model g Admin model g Poster model g Post title content

then, I set the associations like this: User   has_many :admins   has_many :users

Poster   belongs_to :User

If poster belongs_to user then you should also have user has_many or has_one poster. However, going solely on the names of the classes are you sure you want a posters table? Is a poster just a user?

Post   has_many :posts

What?

  belongs_to :Poster

Again you have not got the matching has_many

Admin   has_many: users

Again this does not match the spec in users.

then, when I go to the rails console, I cant make a post that belongs to poster, or a post that belongs to poster...

User.create(:name => "joe") usr = User.last usr.Poster.create() ---- returns an error

What am I doing wrong here?

I think it would be worth your while working right through some tutorails. railstutorial.org is good and is free to use online. Make sure that any tutorial you use is for rails 3 and that you have the right version of rails installed.

Colin

3

Taking a positive spin: the original poster (no pun intended) might be trying to separate concerns, putting the authentication, authorization, and accounting stuff in User, and the stuff having to do with posting, in Poster, thus preventing a common antipattern of User becoming a God Object.

I started doing something similar with one of my side projects, until I found out that Heroku now limits the databases of free apps to a number of *rows*, rather than *bytes* like they used to. :slight_smile:

-Dave