Question

\d users

                                           Table "public.users"
         Column         |            Type             |                     Modifiers                      
------------------------+-----------------------------+----------------------------------------------------
 id                     | integer                     | not null default nextval('users_id_seq'::regclass)
 email                  | character varying(255)      | not null default ''::character varying
 encrypted_password     | character varying(128)      | not null default ''::character varying
 reset_password_token   | character varying(255)      | 
 reset_password_sent_at | timestamp without time zone | 
 remember_created_at    | timestamp without time zone | 
 sign_in_count          | integer                     | default 0
 current_sign_in_at     | timestamp without time zone | 
 last_sign_in_at        | timestamp without time zone | 
 current_sign_in_ip     | character varying(255)      | 
 last_sign_in_ip        | character varying(255)      | 
 created_at             | timestamp without time zone | 
 updated_at             | timestamp without time zone | 
Indexes:
    "users_pkey" PRIMARY KEY, btree (id)
    "index_users_on_email" UNIQUE, btree (email)
    "index_users_on_reset_password_token" UNIQUE, btree (reset_password_token)

\d posts

                                   Table "public.posts"
   Column    |          Type          |                     Modifiers                      
-------------+------------------------+----------------------------------------------------
 id          | integer                | not null default nextval('posts_id_seq'::regclass)
 title       | character varying(100) | not null
 content     | character varying(500) | not null
 created_at  | date                   | 
 updated_at  | date                   | 
 tags        | character varying(55)  | not null default '50'::character varying
 category_id | integer                | not null default 1
Indexes:
    "posts_pkey" PRIMARY KEY, btree (id)

I need to keep track who is post a post, so i need username column in posts table.
Shoud i add a username column in posts table or should i add username in users table or should i create a different table for userdetails with username.

I also need to check whether the user is admin or normal user.

Can anyone post complete relational database schema for this purpose ?

devise User model

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :token_authenticatable, :encryptable, :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  # Setup accessible (or protected) attributes for your model
  attr_accessible :email, :password, :password_confirmation, :remember_me

end

Answer 1

You don’t want a username in your posts table, you just want the user’s ID. The username would go in your users table.

For your users table, you’d want this in the table creation:

t.string, :username, :null => false

and a :limit if you want to limit the length. Then in your User class:

validates :username, :uniqueness => { :case_sensitive => false }
has_many :posts

If you don’t want usernames to be unique then you could drop the validates :username; you could also downcase the usernames in a before_validate hook and add a unique index on username to your users table. You might want some flags on the has_many, see the guide for details.

Then, when creating posts:

t.integer, :user_id, :null => false

and in Post:

belongs_to :user

Then you can get the username for a post through its user:

p.user.username

If you’re trying to add usernames to existing data then you’d need :null => true in your migrations for the new columns and you’d have to figure out what you want to do with the missing values in your existing data.

I don’t know how any of this would integrate with devise (sorry, I don’t use it) or if devise will even care about usernames. Hopefully someone else can fill in the devise parts (if any) and leave me a comment if they do.