Single Table Inheritance implementation

I want to change the "type" field for a table but am getting an error:
read_creatures.rb:19: undefined local variable or method `green_dragon'

I've tried both "green_dragon" and the class name "GreenDragon" with both
giving (different) errors :frowning:

thufir@arrakis ~/Desktop/dwemthys $
thufir@arrakis ~/Desktop/dwemthys $ ruby make_creatures.rb
-- create_table(:creatures)
  SQL (0.023529) CREATE TABLE creatures ("id" INTEGER PRIMARY KEY NOT
NULL, "type" varchar(255) DEFAULT NULL, "life" integer DEFAULT NULL,
"strength" integer DEFAULT NULL, "charisma" integer DEFAULT NULL,
"weapon" integer DEFAULT NULL)
   -> 0.1483s
#<Dragon:0xb7747f54 @new_record=true, @attributes={"strength"=>0,
"type"=>"Dragon", "charisma"=>0, "weapon"=>0, "life"=>0}>
  SQL (0.000930) INSERT INTO creatures ("strength", "type", "charisma",
"life", "weapon") VALUES(0, 'Dragon', 0, 0, 0)
#<Dragon:0xb773e2ec @new_record=true, @attributes={"strength"=>0,
"type"=>"Dragon", "charisma"=>0, "weapon"=>0, "life"=>0}>
  SQL (0.000742) INSERT INTO creatures ("strength", "type", "charisma",
"life", "weapon") VALUES(0, 'Dragon', 0, 0, 0)
#<Dragon:0xb773bb8c @new_record=true, @attributes={"strength"=>0,
"type"=>"Dragon", "charisma"=>0, "weapon"=>0, "life"=>0}>
  SQL (0.000735) INSERT INTO creatures ("strength", "type", "charisma",
"life", "weapon") VALUES(0, 'Dragon', 0, 0, 0)
#<Dragon:0xb77394b8 @new_record=true, @attributes={"strength"=>0,
"type"=>"Dragon", "charisma"=>0, "weapon"=>0, "life"=>0}>
  SQL (0.001781) INSERT INTO creatures ("strength", "type", "charisma",
"life", "weapon") VALUES(0, 'Dragon', 0, 0, 0)
#<Dragon:0xb7734440 @new_record=true, @attributes={"strength"=>0,
"type"=>"Dragon", "charisma"=>0, "weapon"=>0, "life"=>0}>
  SQL (0.000739) INSERT INTO creatures ("strength", "type", "charisma",
"life", "weapon") VALUES(0, 'Dragon', 0, 0, 0)
thufir@arrakis ~/Desktop/dwemthys $
thufir@arrakis ~/Desktop/dwemthys $ ruby read_creatures.rb
  Creature Load (0.006906) SELECT * FROM creatures
  Dragon Update (0.001537) UPDATE creatures SET "charisma" = 0,
"strength" = 0, "weapon" = 0, "life" = 0, "type" = 'Dragon' WHERE "id" = 1
  Dragon Update (0.000748) UPDATE creatures SET "charisma" = 0,
"strength" = 0, "weapon" = 0, "life" = 0, "type" = 'Dragon' WHERE "id" = 2
  Dragon Update (0.000731) UPDATE creatures SET "charisma" = 0,
"strength" = 0, "weapon" = 0, "life" = 0, "type" = 'Dragon' WHERE "id" = 3
read_creatures.rb:19: undefined local variable or method `green_dragon'
for main:Object (NameError)
        from read_creatures.rb:17:in `each'
        from read_creatures.rb:17
thufir@arrakis ~/Desktop/dwemthys $
thufir@arrakis ~/Desktop/dwemthys $ cat read_creatures.rb
require 'fileutils'
require 'active_record'
require 'creature'
require 'dragon'
require 'green_dragon'

ActiveRecord::Base.logger = Logger.new(STDERR)
ActiveRecord::Base.colorize_logging = true

ActiveRecord::Base.establish_connection(
    :adapter => "sqlite3",
    :dbfile => "dwemthys.db"
)

index = 0
Creature.find(:all).each { |creature|
        if (index > 2) then
                creature.type = green_dragon
                creature.weapon = 1000
        end
        creature.save
        index = index+1
}

Creature.find(:all).each { |creature|
        puts creature.inspect
}
thufir@arrakis ~/Desktop/dwemthys $

thanks,

Thufir

Ohhh, it's a string. So, the following worked:

thufir@arrakis ~/Desktop/dwemthys $
thufir@arrakis ~/Desktop/dwemthys $ cat read_creatures.rb
require 'fileutils'
require 'active_record'
require 'creature'
require 'dragon'
require 'green_dragon'

ActiveRecord::Base.logger = Logger.new(STDERR)
ActiveRecord::Base.colorize_logging = true

ActiveRecord::Base.establish_connection(
    :adapter => "sqlite3",
    :dbfile => "dwemthys.db"
)

index = 0
Creature.find(:all).each { |creature|
        if (index > 2) then
                creature.type = "GreenDragon" #MUST be a string!
                creature.weapon = 1000
        end
        creature.save
        index = index+1
}

Creature.find(:all).each { |creature|
        puts creature.inspect
}
thufir@arrakis ~/Desktop/dwemthys $

thanks,

Thufir