creating with a belongs_to has_many association - ruby-on-rails-3

Question

I'm getting the error unknown attribute: user_id durring execution of #user.posts.create in my specs
User Class
class User < ActiveRecord::Base
# new columns need to be added here to be writable through mass assignment
attr_accessible :username, :email, :password, :password_confirmation
has_many :posts, :dependent => :destroy
end
Post Class
class Post < ActiveRecord::Base
attr_accessible :title, :body
belongs_to :user
end
DB Schema
ActiveRecord::Schema.define(:version => 20111214045425) do
create_table "posts", :force => true do |t|
t.string "title"
t.string "body"
t.integer "user_id"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "users", :force => true do |t|
t.string "username"
t.string "email"
t.string "password_hash"
t.string "password_salt"
t.datetime "created_at"
t.datetime "updated_at"
end
end
Any help? I've followed every guide I can find for using ActiveRecord. All I want to do is create a Post with an associated User.

Answer 1

You can use
#user = User.find(1)
#post = #user.posts.build(posts_attributes_as_hash)
#post.save
Or even
post = Post.new(posts_attributes)
#user = User.find(1)
#user.posts << post
Edit
To use create directly:
#user = User.find(1)
#post = #user.posts.create(posts_attributes_as_hash)
For more information have a look at has_many-association-reference especially at section called 4.3.1 Methods Added by has_many
New Edit:
I created a new project with your code and in rails console I tried the following commands
User.create(:username => "UserNamedTest", :email => "usernamedtest#somewhere.com")
SQL (13.6ms) INSERT INTO "users" ("created_at", "email", "password_hash", "password_salt", "updated_at", "username") VALUES (?, ?, ?, ?, ?, ?) [["created_at", Wed, 14 Dec 2011 09:02:46 UTC +00:00], ["email", "usernamedtest#somewhere.com"], ["password_hash", nil], ["password_salt", nil], ["updated_at", Wed, 14 Dec 2011 01:03:26 UTC +00:00], ["username", "UserNamedTest"]]
=> #<User id: 2, username: "UserNamedTest", email: "usernamedtest#somewhere.com", password_hash: nil, password_salt: nil, created_at: "2011-12-14 09:02:46", updated_at: "2011-12-14 09:02:46">
user = User.find_by_username("UserNamedTest")
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."username" = 'UserNamedTest' LIMIT 1
=> #<User id: 2, username: "UserNamedTest", email: "usernamedtest#somewhere.com", password_hash: nil, password_salt: nil, created_at: "2011-12-14 09:02:46", updated_at: "2011-12-14 09:02:46">
new_post = user.posts.create(:title => "just a test", :body =>"body of article test")
SQL (0.5ms) INSERT INTO "posts" ("body", "created_at", "title", "updated_at", "user_id") VALUES (?, ?, ?, ?, ?) [["body", "body of article test"], ["created_at", Wed, 14 Dec 2011 09:03:59 UTC +00:00], ["title", "just a test"], ["updated_at", Wed, 14 Dec 2011 09:03:59 UTC +00:00], ["user_id", 2]]
=> #<Post id: 2, title: "just a test", body: "body of article test", user_id: 2, created_at: "2011-12-14 09:03:59", updated_at: "2011-12-14 09:03:59">
irb(main):022:0> new_post.inspect
=> "#<Post id: 2, title: \"just a test\", body: \"body of article test\", user_id: 2, created_at: \"2011-12-14 09:03:59\", updated_at: \"2011-12-14 09:03:59\">"
From what I see the code is ok, the post get created with no errors

Answer 2

Discovered the issue after a dump of the test.sqlite3 schema. user_id was not defined as a column in the db. Blowing out the database and running rake spec migrates the database and fixes everything.