Code for an object mapper using plain ruby objects. Goal: make it easier to focus on creating objects based on behavior and only care about persistence at the very end

gistfile1.txt

mysql = MysqlStore.new
person_mapper = mysql.generate_table_mapping("person") do
  map :first_name
  map :last_name
  map :dob, :dob_to_s_db
end

a = Person.new
a.first_name = "Ryan"
a.last_name = "Briones"
a.dob_year = 1982
a.dob_month = 8
a.dob_date = 30

person_mapper.store(a)

mysql_store.rb

class MysqlStore
  def store(mapping, object)
    puts "INSERT INTO #{mapping.table_name} (#{mapping.get_mapped_column_names.join(', ')}) VALUES (#{mapping.get_mapped_column_names.map { |a| mapping.get_value_on_for_column(object, a).inspect }.join(', ')})"
  end
  
  def generate_table_mapping(table, &block)
    TableMapping.new(self, table, &block)
  end
  
  class TableMapping
    def initialize(store, table, &block)
      @store = store
      @table = table
      
      instance_eval(&block)
    end
    
    def table_name
      @table
    end
    
    def map(db_column, data_source = nil)
      @map ||= {}
      @map[db_column.to_s] = (data_source || db_column.to_s)
    end
    
    def get_mapping(db_column)
      @map ||= {}
      @map[db_column.to_s]
    end
    
    def get_mapped_column_names
      @map.keys
    end
    
    def get_value_on_for_column(object, attribute)
      object.send(get_mapping(attribute)) if get_mapping(attribute)
    end
    
    def store(object)
      @store.store(self, object)
    end
  end
end

person.rb

class Person
  attr_accessor :first_name, :last_name, :dob_month, :dob_date, :dob_year
  
  def dob
    Date.civil(dob_year, dob_month, dob_date)
  end
  
  def dob_to_s_db
    Time.mktime(dob_year, dob_month, dob_date).strftime("%Y-%m-%d")
  end
end