Datamapper DataMapper

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  phatmann October 2nd, 2009 @ 12:39 PM

  Here is a lame monkeypatch for people that need a fix now. I am not yet sure what the best long-term fix is.

  module DataMapper
    module Migrations
      module DataObjectsAdapter
        module ClassMethods
          alias _type_map type_map
          def type_map
            t = _type_map.dup
            t[Types::Yaml]  = { :primitive => 'TEXT' }
            t
          end
        end
      end
    end
  end
  

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  Jordan Ritter October 2nd, 2009 @ 03:04 PM

  I solved this with a different approach.

  FWIW, I'll speculate that the Text "class primitive" went away because DM already had a "text" class primitive (called String). Given DM's stated intent of remaining generalizable over RDBMS-specific implementations: having two class primitives for "text" objects -- which were/are necessary because of specific RDBMS implementations (VARCHAR vs. CLOB/*TEXT) -- maybe was seen both as a high-level philosophical DRY contradiction and a general "this is against our stated religion". Not that DM devs are inflexible -- because they've been quite happy to fix and extend things.

  However, for the vast majority of us, DM is our window into an RDBMS. And those RDBMS's sometimes use different fields for (objectively) the same data (i.e. VARCHAR vs. TEXT), just with different limitations. So we need this functionality.
  

  My approach was to change how the type_map looks up what the underlying schema primitive is, instead looking at the property.type's ancestry and using theirs. There are places in the DM code that recognize the class type ::DM::Types::Text and convert its underlying schema primitive to 'TEXT'; therefore deriving a YAML type from ::Text type would result in the same schema primitive being used. This has the added bonus that the recently-added field auto-sizing feature (via :length) works as expected.

  For example:

  module DataMapper
  module Types

  class Yaml < DataMapper::Types::Text
    primitive String
    # ...
  end
  

  end end

  Then:

  class Foo
  property :bar, Yaml, :length => 2**24-1 end

  Would result in a MEDIUMTEXT being used in MySQL for the field.

  This requires a change in dm-core (http://github.com/jpr5/dm-core/commit/bd8ad8979a66cc47f885d9e2a5bdc..., and updates to dm-more's Csv, Yaml and Json types (http://github.com/jpr5/dm-more/commit/9c970d2120bb4b740989597ec02f5....

• 

  Dan Kubb (dkubb) October 3rd, 2009 @ 02:20 AM

  • State changed from “new” to “accepted”
  • Assigned user set to “Dan Kubb (dkubb)”

  I actually think perhaps we should make Text a primitive in the short-term, and then make sure the Csv, Yaml and Object types use Text as a primitive.

  The long term approach will be to have DM::Property subclasses, and put custom types and properties on equal footing. There won't be anything special about custom types vs. Property
  objects, and serialization methods will be able to be defined on a per Property basis.

• 

  Dan Kubb (dkubb) October 6th, 2009 @ 12:38 PM

  • State changed from “accepted” to “resolved”

  This is now resolved in dm-core/master.