On Sep 19, 2009, at 5:35 PM, Fidel Viegas wrote: > Hi all, > > I am implementing a simple invoice system where I have invoiceLines, > and where I want to keep the order of the lines. I have tried to > google around but have not found any sample on this. > > Can someone give me a pointer to something that uses a set where the > order is kept? > > Thanks in advance. > > Regards, > > Fidel.
Well, that would be an Array. Or in the likely case that your data is accessed with ActiveRecord models, an AssociationProxy that will behave mostly like an Array. You will probably find something like the following in any reasonable discussion about the has_many/ belongs_to associations. If you don't specify a default order for the association, then you'll get the invoice_lines back in whatever order the database prefers (often the order in which the database records were created). ## Models class Invoice < ActiveRecord::Base has_many :invoice_lines, :order => 'line_number' end class InvoiceLine < ActiveRecord::Base belongs_to :invoice end ## migration (schema) create_table :invoices do |t| t.integer :number t.date :inv_date t.date :due_date # etc. end create_table :invoice_lines do |t| t.references :invoice # equiv. to t.integer :invoice_id t.integer :line_number t.string :sku t.integer :quantity t.decimal :unit_price, :precision => 8, :scale => 2 # etc. end ## use in a controller @invoice = Invoice.find_by_number(params[:invoice][:number]) @invoice.invoice_lines #=> an array-like set of InvoiceLine records -Rob Rob Biedenharn http://agileconsultingllc.com [email protected] --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
