Metaprogramming Ruby 2

The Story of Bob, Metaprogrammer

Bob, a newcomer to Ruby, has a grand plan: he’ll write the biggest Internet social network ever for movie buffs. To do that, he needs a database of movies and movie reviews. Bob makes it a practice to write reusable code, so he decides to build a simple library to persist objects in the database.

Bob’s First Attempt

Bob’s library maps each class to a database table and each object to a record. When Bob creates an object or accesses its attributes, the object generates a string of SQL and sends it to the database. All this functionality is wrapped in a class:

the_m_word/orm.rb

class Entity
  attr_reader :table, :ident

  def initialize(table, ident)
    @table = table
    @ident = ident
 Database.sql ...