Has_many :through and named_scope

Rails
1

Hi
I have the models roles, users and user_roles. The relationship among
them is

user.r

user has_many user_roles
user has_many roles, :through => :user_roles

role.rb

role has_many user_roles
role has_many users, :through => :user_roles

user_role.rb

belongs_to :user
belongs_to :role

 Suppose a login user1 has roles [admin, staff] And login user2 has

only one role say [participant] Now how can I check the cases

1)a login user is an admin or staff
2) a login user has_role participant?

  And also I would like to know whether this can be written using

named scopes.(I am totally new to named scopes)

Thanks in advance
Tom

2

user1.roles returns an array of roles.
The array class has a function “include?(obj)” that returns true or
false.

Something like this should work:
user1.roles.include?(Role.find_by_name(‘admin’))

Named scopes are not ment for stuff like this.
You can create a function on the user model “is_admin?” for the code
above. That way if how an admin is defined changes, you only need to
update the code in one place.

3

Better off saying !roles.find_by_name(“admin”).blank?
Saves on SQL

Blog: http://random8.zenunit.com/
Twitter: http://twitter.com/random8r
Learn: http://sensei.zenunit.com/
New video up now at http://sensei.zenunit.com/ real fastcgi rails
deploy process! Check it out now!