Module: DataMapper::Associations::ManyToMany

Extended by:
DataMapper::Assertions
Defined in:
lib/dm-core/associations/many_to_many.rb

Defined Under Namespace

Classes: Proxy

Class Method Summary collapse

Methods included from DataMapper::Assertions

assert_kind_of

Class Method Details

.setup(name, model, options = {}) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Setup many to many relationship between two models -



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# File 'lib/dm-core/associations/many_to_many.rb', line 10

def self.setup(name, model, options = {})
  assert_kind_of 'name',    name,    Symbol
  assert_kind_of 'model',   model,   Model
  assert_kind_of 'options', options, Hash

  repository_name = model.repository.name

  model.class_eval <<-EOS, __FILE__, __LINE__
    def #{name}(query = {})
      #{name}_association.all(query)
    end

    def #{name}=(children)
      #{name}_association.replace(children)
    end

    private

    def #{name}_association
      @#{name}_association ||= begin
        unless relationship = model.relationships(#{repository_name.inspect})[#{name.inspect}]
          raise ArgumentError, "Relationship #{name.inspect} does not exist in \#{model}"
        end
        association = Proxy.new(relationship, self)
        parent_associations << association
        association
      end
    end
  EOS

  opts = options.dup
  opts.delete(:through)
  opts[:child_model]              ||= opts.delete(:class_name)  || Extlib::Inflection.classify(name)
  opts[:parent_model]             =   model
  opts[:repository_name]          =   repository_name
  opts[:remote_relationship_name] ||= opts.delete(:remote_name) || Extlib::Inflection.tableize(opts[:child_model])
  opts[:parent_key]               =   opts[:parent_key]
  opts[:child_key]                =   opts[:child_key]
  opts[:mutable]                  =   true

  names        = [ opts[:child_model], opts[:parent_model].name ].sort
  model_name   = names.join
  storage_name = Extlib::Inflection.tableize(Extlib::Inflection.pluralize(names[0]) + names[1])

  opts[:near_relationship_name] = Extlib::Inflection.tableize(model_name).to_sym

  model.has(model.n, opts[:near_relationship_name])

  relationship = model.relationships(repository_name)[name] = RelationshipChain.new(opts)

  unless Object.const_defined?(model_name)
    model = DataMapper::Model.new(storage_name)

    model.class_eval <<-EOS, __FILE__, __LINE__
      def self.name; #{model_name.inspect} end
      def self.default_repository_name; #{repository_name.inspect} end
      def self.many_to_many; true end
    EOS

    names.each do |n|
      model.belongs_to(Extlib::Inflection.underscore(n).to_sym)
    end

    Object.const_set(model_name, model)
  end

  relationship
end