Relationship between Customer, Person, Employee, User entity

rubyonrails-talk
1

Hello Friends,

I am trying to define relationship between real-world entities in my application.... But I am feel, I am over-representing it a little and hence would like your opinion.

class User < ActiveRecord::Base   has_and_belongs_to_many :user_groups

  attr_accessible :username, :email, :password, :password_confirmation

end

class Customer < User   has_many :orders

  belongs_to :person end

class Employee < User   belongs_to :person

end

class Person < ActiveRecord::Base   has_many :addresses end

Should I merge User and Person Models? Basically user has only login information while Person has details like first_name, last_name, address and so on....

Also, should Customer and Employee inherit from Person or User? Trying to normalize stuff but dont want to over-normalize it too..

Thank you.

2

Hello Friends,

I am trying to define relationship between real-world entities in my application.... But I am feel, I am over-representing it a little and hence would like your opinion.

class User < ActiveRecord::Base has_and_belongs_to_many :user_groups

attr_accessible :username, :email, :password, :password_confirmation

end

class Customer < User has_many :orders

belongs_to :person end

class Employee < User belongs_to :person

end

class Person < ActiveRecord::Base has_many :addresses end

Should I merge User and Person Models? Basically user has only login information while Person has details like first_name, last_name, address and so on....

Yes, why complicate matters.

Have you considered that a user might be both a customer and an employee? Your model would preclude that I think. Are you sure it would not be better just to have the user model who can be either or both just by attribute contents?

Colin

3

I think the differences between Customer and Employee is Role, when you assign a ‘customer’ role, he is a customer.

So you could use Role to distinguish different person, and a person may have many roles

class User < ActiveRecord::Base

has_many :roles

has_many :addresses

end

4

Colin Law wrote:

Yes, why complicate matters.

Have you considered that a user might be both a customer and an employee? Your model would preclude that I think. Are you sure it would not be better just to have the user model who can be either or both just by attribute contents?

Colin

Valid point :slight_smile:

I do not want to combine Customer and Employee tables because they have quite different attributes...

Employee has department, manager, roles etc... Customer has current status, credit card info etc.. bunch of stuff I will collect on registration.. If I combine them, the resulting table will be a little too huge..

5

Assuming you plan to use STI for the tables then the table contains all the attributes for both anyway. Presumably most of the stuff is varchar which are variable length fields. so consume very little space. How many million customers are you expecting so that db size becomes a factor? :slight_smile:

Colin