Rails - Aug 2005 - Active Record problem

Hi all
I am new to Rails, and obviously I''m missing something, I''ll
get straight to the question:
 
A User has many operations (granted to her), each Operation is associated with
an OperationType. Each Operation may be associated with more then one User.
 
So the model goes like this:
 
class User < ActiveRecord::Base           
 has_and_belongs_to_many :operations          
end
 
class Operation <ActiveRecord::Base
  belongs_to :operation_type,
  has_and_belongs_to_many :users
end
 
class OperationType <ActiveRecord::Base
 has_many :operations
end
 
And I have users, operations, operations_users (join table) &
operation_types tables as needed.
 
Now for a given user, I want to fetch all the types of the operations associated
with her (OperationType classes).
So there is one very inefficient way that goes like this:
 
(suppose user_id holds the user id)
user = User.find(user_id)
user_operations = user.operations
@user_operation_types = Array.new
for op in user_operations    
    operation_type = op.operation_type
    if !@user_operation_types.include? operation_type 
        @user_operation_types << operation_type 
    end
end
 
And I get all the operation types associated with the user''s operations
in the @user_operation_types array. But this is inefficient (many selects) and
doesn''t seem good.
I tried to change the first line to: user = User.find(user_id, :include=>
:operations)
but then I get only one entry in the @user_operation_types array, which is
incorrect (there should be more).
 
What is the right way to do this?
 
Thanks for your help
Nadav




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Nadav,

I haven''t worked much with has_and_belongs_to_many but I think if you
change
the line

has_and_belongs_to_many :operations

--to--

has_and_belongs_to_many :operations, :join_table =>
"operations_users"

you should be able to access all operations for a user by @user.operations

Again, not sure...but this seems like this is the correct way to do it.



-- 
Andrew Stone


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