Module: ActiveWarehouse::HierarchicalDimension::ClassMethods

Defined in:
lib/active_warehouse/dimension/hierarchical_dimension.rb

Overview

:nodoc

Instance Method Summary collapse

Instance Method Details

#acts_as_hierarchy_dimension ⇒ Object Also known as: acts_as_hierarchical_dimension

Indicates that a dimension is a variable-depth hierarchy.



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# File 'lib/active_warehouse/dimension/hierarchical_dimension.rb', line 11

def acts_as_hierarchy_dimension
  unless hierarchical_dimension?
     class << self
       # Get the bridge class for this dimension
       def bridge_class
         unless @bridge_class
           unless Object.const_defined?(bridge_class_name.to_sym)
             Object.const_set(bridge_class_name.to_sym, Class.new(ActiveWarehouse::Bridge))
           end
           @bridge_class = Object.const_get(bridge_class_name.to_sym)
         end
         @bridge_class
       end

       # Get the bridge class name for this hierarchical dimension
       def bridge_class_name
         @child_hierarchy_relationship.class_name || @parent_hierarchy_relationship.class_name
       end

      # Define the child relationship on the bridge table to the dimension
      # table. We can specify a different class name for the bridge table
      # and different foreign-key.
      def child_bridge(association_id, options = {})
        options[:class_name] ||= name.gsub(/Dimension$/, 'HierarchyBridge')
        options[:foreign_key] ||= "parent_id"
        has_many association_id, options
        @child_hierarchy_relationship = reflections[association_id]
      end

      # Define the parent relationship on the bridge table to the dimension
      # table. 
      def parent_bridge(association_id, options = {})
        options[:class_name] ||= name.gsub(/Dimension$/, 'HierarchyBridge')
        options[:foreign_key] ||= "child_id"
        has_many association_id, options
        @parent_hierarchy_relationship = reflections[association_id]
      end

      # the foreign key column name on the bridge table for finding the
      # children.
      def child_foreign_key
        @child_hierarchy_relationship.primary_key_name
      end
      
      # the foreign key column name on the bridge table for finding the
      # parent.
      def parent_foreign_key
        @parent_hierarchy_relationship.primary_key_name
      end
      
      # the column name on the bridge table that defines the number of levels
      # from the parent
      def levels_from_parent
        bridge_class.levels_from_parent
      end
     end
  end
  include InstanceMethods
end

#hierarchical_dimension? ⇒ Boolean

Return true if this is a hierarchical dimension

Returns:

  • (Boolean) 


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# File 'lib/active_warehouse/dimension/hierarchical_dimension.rb', line 73

def hierarchical_dimension?
  self.included_modules.include?(InstanceMethods)
end