attribute.rb in rails-erd-0.1.1

- old
+ new

@@ -1,7 +1,9 @@
 # -*- encoding: utf-8
 module RailsERD
+  # Describes an entity's attribute. Attributes correspond directly to
+  # database columns.
   class Attribute
     TIMESTAMP_NAMES = %w{created_at created_on updated_at updated_on} #:nodoc:
 
     class << self
       def from_model(domain, model) #:nodoc:
@@ -9,34 +11,46 @@
       end
     end
 
     attr_reader :column #:nodoc:
   
-    def initialize(domain, model, column)
+    def initialize(domain, model, column) #:nodoc:
       @domain, @model, @column = domain, model, column
     end
     
+    # The name of the attribute, equal to the column name.
     def name
       column.name
     end
     
+    # The type of the attribute, equal to the Rails migration type. Can be any
+    # of +:string+, +:integer+, +:boolean+, +:text+, etc.
     def type
       column.type
     end
     
+    # Returns +true+ if this attribute is mandatory. Mandatory attributes
+    # either have a presence validation (+validates_presence_of+), or have a
+    # <tt>NOT NULL</tt> database constraint.
     def mandatory?
       !column.null or @model.validators_on(name).map(&:kind).include?(:presence)
     end
     
+    # Returns +true+ if this attribute is the primary key of the entity.
     def primary_key?
       @model.arel_table.primary_key == name
     end
   
+    # Returns +true+ if this attribute is used as a foreign key for any
+    # relationship.
     def foreign_key?
       @domain.relationships_for(@model).map(&:associations).flatten.map(&:primary_key_name).include?(name)
     end
     
+    # Returns +true+ if this attribute is one of the standard 'magic' Rails
+    # timestamp columns, being +created_at+, +updated_at+, +created_on+ or
+    # +updated_on+.
     def timestamp?
       TIMESTAMP_NAMES.include? name
     end
     
     def <=>(other) #:nodoc:
@@ -49,9 +63,17 @@
   
     def to_s #:nodoc:
       name
     end
   
+    # Returns a short description of the attribute type. If the attribute has
+    # a non-standard limit or if it is mandatory, this information is included.
+    #
+    # Example output:
+    # <tt>:integer</tt>:: int
+    # <tt>:string, :limit => 255</tt>:: str
+    # <tt>:string, :limit => 128</tt>:: str (128)
+    # <tt>:boolean, :null => false</tt>:: bool *
     def type_description
       case type
       when :integer       then "int"
       when :float         then "float"
       when :decimal       then "dec"