ActiveRecord::Base Without Table

Question

This came up a bit ago ( rails model attributes without corresponding column in db ) but it looks like the Rails plugin mentioned is not maintained ( http://agilewebdevelopment.com/plugins/activerecord_base_without_table ). Is there no way to do this with ActiveRecord as is?

If not, is there any way to get ActiveRecord validation rules without using ActiveRecord?

ActiveRecord wants the table to exist, of course.

Answer 1

This is an approach I have used in the past:

In app/models/tableless.rb

class Tableless < ActiveRecord::Base
  def self.columns
    @columns ||= [];
  end

  def self.column(name, sql_type = nil, default = nil, null = true)
    columns << ActiveRecord::ConnectionAdapters::Column.new(name.to_s, default,
      sql_type.to_s, null)
  end

  # Override the save method to prevent exceptions.
  def save(validate = true)
    validate ? valid? : true
  end
end

In app/models/foo.rb

class Foo < Tableless
  column :bar, :string  
  validates_presence_of :bar
end

In script/console

Loading development environment (Rails 2.2.2)
>> foo = Foo.new
=> #<Foo bar: nil>
>> foo.valid?
=> false
>> foo.errors
=> #<ActiveRecord::Errors:0x235b270 @errors={"bar"=>["can't be blank"]}, @base=#<Foo bar: nil>>