Hez's Bloggity Blog

Recently discovered some quirks while working with Datamapper (ver 0.10.2). If you want to fetch deleted objects you need to use the syntax:

Model.with_deleted { Model.all }

Which by the way will only find deleted objects, if you want all the objects your going to have to do something like

Model.with_deleted { Model.all } | Model.all

The next quirky bit is if you want to undelete things you can't simply do:

m = Model.with_deleted { Model.get(1) }
m.update( :deleted_at => nil )

You actually have to do:

m = Model.with_deleted { Model.get(1) }
m.deleted_at
m.update( :deleted_at => nil )

Due to the lazy loading that Datamapper does it actually doesn't load the :deleted_at property until you have accessed and apparently won't save changes to it either.

Full example:

class Test
  include DataMapper::Resource
  
  property :id, Serial
  property :deleted_at, ParanoidDateTime
end

t = Test.new
t.save                          #~ (0.354887) INSERT INTO "tests" DEFAULT VALUES
t = Test.new
t.save                          #~ (0.089852) INSERT INTO "tests" DEFAULT VALUES
t = Test.first                  #~ (0.000191) SELECT "id" FROM "tests" WHERE "deleted_at" IS NULL ORDER BY "id" LIMIT 1
t.destroy                       #~ (0.002124) UPDATE "tests" SET "deleted_at" = '2010-04-15T17:02:14-07:00' WHERE "id" = 1
t = Test.with_deleted { Test.first }  #~ (0.000092) SELECT "id" FROM "tests" WHERE NOT("deleted_at" IS NULL) ORDER BY "id" LIMIT 1
t.deleted_at = nil
t.save                          # true
t = Test.with_deleted { Test.first }  #~ (0.000094) SELECT "id" FROM "tests" WHERE NOT("deleted_at" IS NULL) ORDER BY "id" LIMIT 1
t.deleted_at                    #~ (0.000429) SELECT "id", "deleted_at" FROM "tests" WHERE "id" = 1 ORDER BY "id"