Question

I have an existing legacy Firebird database with nonstandard table and field names.

I would like to write a Sinatra app that can access it and display information. I’ve seen stuff like dm-is-reflective that appears to work when a database has proper naming conventions, but how do I use DataMapper (or ActiveRecord whichever is the easiest) to access those tables?

For example, assuming I had these two tables:

Bookshelfs
    shelf_id: integer
    level: integer
    created: timestamp

Book
    id: integer
    id_of_shelf: integer
    title: string
    pages: integer

Something like with odd naming conventions that don’t follow any set pattern and where one table’s record might “own” multiple entries in another table even though there is not foreign_key assigned.

How would you set up datamapper (or activerecord) to communicate with it?

Answer 1

Look in to this gem to get setup with ActiveRecord on Sinatra:
https://github.com/bmizerany/sinatra-activerecord

As for how to define the relations, activerecord can do this easily.

class Book < ActiveRecord::Base
  belongs_to :bookshelf, :class_name => 'Bookshelf', :foreign_key => 'id_of_shelf'
end

class Bookshelf < ActiveRecord::Base
  has_many :books, :class_name => 'Book', :foreign_key => 'id_of_shelf'
end