cheat sheets.

--- datamapper version 4	Fri Oct 16 17:24:19 -0700 2009
+++ datamapper version 9	Wed Sep 21 15:18:08 -0700 2011
@@ -1,132 +1,133 @@
 DataMapper, the ruby object relational mapper
   website:  http://www.datamapper.org
   git:      git://github.com/datamapper/dm-core.git
   mail:     http://groups.google.com/group/datamapper
   now:      http://www.twitter.com/datamapper
             irc://irc.freenode.net/datamapper
             irc://irc.freenode.net/dm-hacking
-  before:   http://irclogger.com/datamapper/
-            http://irclogger.com/dm-hacking/
-  bugs:     http://datamapper.lighthouseapp.com/projects/20609-datamapper/
+  before:   http://irclogger.com/.datamapper/
+            http://irclogger.com/.dm-hacking/
+  bugs:     https://github.com/datamapper/dm-core/issues
 
 Setting up a Connection
   DataMapper.setup(:default, "adapter://user:password@hostname/dbname")
-  supported adapters: mysql, sqlite3, postgres, sqlite3::memory:
+  supported adapters: mysql, sqlite, postgres, sqlite::memory:
   additional adapters are in dm-more, (couchdb, rest, imap, file, saleforce...)
+  in-memory adapter: DataMapper.setup(:default, :adapter => 'in_memory')
 
 Creating a Model (with properties)
   class Zoo
     include DataMapper::Resource
     property :id, Serial
   end
 
 
 Properties
   property :id,   Serial               # auto-incrementing PK
   property :name, String, :key => true # natural key
     # you must specify >= 1 key, CPK support 100%
 
   # available data-types
   property :description, Text # (lazy by default)
   property :created_at,  DateTime
   property :open,        Boolean
   property :admission,   BigDecimal
 
-  # require dm-types for Csv, Enum, EpochTime, FilePath, Flag, 
-  #  IPAddress, URI, Yaml
+  # require dm-types for Csv, Enum, EpochTime, FilePath, Flag,
+  #  IPAddress, URI, Yaml and more
 
 Property Options (pass as hash)
-  :default, :nullable, :field (column name), :size, :length, :format,
+  :default, :required, :field (column name), :size, :length, :format,
   :index, :unique_index, :ordinal, :auto_validation, :precision,
   :scale, :accessor, :reader, :writer, :lazy
 
 
 Finders
   Zoo.get(PK_HERE)
   Zoo.first({see_below})
   Zoo.all({see_below})
 
 Finder Options (pass as hash)
   :conditions => ["property = ? and property = ?", 'value', 'value']
   :conditions => {:property => 'value', ...}
   :property => 'ZooNameHere' 
      # any non-standard key => value pair is assumed a condition if not 
      # otherwise recognized
   :property.lte => 12.00  # <=
            .gte           # >=
            .gt            # >
            .lt            # <
            .not           # NOT =
            .like          # LIKE
            .in            # IN ()
   'class.property' => 'value'
   Class.relationship.property => 'value' # will automatically issue JOINS
 
 Finder Gotcha
   :order => [:created_at.desc, ...] # descending sort
                         .asc        # ascending
 
 
 Associations
   has 1                    # has_one
   has n                    # has_many
-  belongs_to :things   
-  has n, :things, :through =&gt; :more_things
+  belongs_to :thing
+  has n, :more_things, :through =&gt; :things
   has n, :things, :through => Resource # has_and_belongs_to_many
 
 Association Options
   (any Finder Options)
-  :class_name =&gt; 'ClassNameHere'
+  :model =&gt; 'ClassNameHere'
   :order => [:property.desc]
   :child_key => [:property, ...]
   :through => :other_association
 
 
 Validations (require 'dm-validations')
-  validates_present     :title
-  validates_is_number   :rating
-  validates_format      :email, :as =&gt; :email_address
-  validates_length      :summary, :in =&gt; (1..100)
-  validates_is_unique   :slug
+  validates_presence_of     :title
+  validates_numericality_of :rating
+  validates_format_of       :email, :as =&gt; :email_address
+  validates_length_of       :summary, :in =&gt; (1..100)
+  validates_uniqueness_of   :slug
   validates_with_method (do...end, :method_name)
 
 
 Callbacks AKA "Hooks"
   Object-level
     before :method_name, (do...end, :another_method_name)
     after  :method_name, (do...end, :another_method_name)
   Class-level
     before_class_method :method_name, (do...end, :another_method_name)
     after_class_method  :method_name, (do...end, :another_method_name)
 
 Callbacks Gotcha
   Hooks act on 'self' and aren't passed an arguement
   'self' for object-level hooks are the instance
   'self' for class-level hooks are the class itself
 
 Misc. Stuff & Gotchas
   Single Table Inheritance
     property :type, Discriminator # then inherit from this model
 
   Paranoia
     property :deleted_at, ParanoidDateTime
     property :deleted,    ParanoidBoolean
 
   Multiple DB Connections
     DataMapper.setup(:external, "adapter://username:password@hostname/dbname")
-    repository(:external) do...end
+    DataMapper.repository(:external) do...end
     Association: has n, :things, :repository => repository(:external)
     Finder: Thing.all(:repository => repository(:external))
 
+    DataMapper.setup(:colors_db,  &quot;sqlite3:path/to/colors.db&quot;)
     class Color
        include DataMapper::Resource
-  
-       DataMapper.setup(:colors_db,  &quot;sqlite3:path/to/colors.db&quot;)
+
 
        def self.default_repository_name
          :colors_db
        end
 
        property :name, String
     end