: RailsERD::Domain::Relationship [Rails ERD

Describes a relationship between two entities. A relationship is detected based on Active Record associations. One relationship may represent more than one association, however. Related associations are grouped together. Associations are related if they share the same foreign key, or the same join table in the case of many-to-many associations.

Methods

Classes and Modules

Class RailsERD::Domain::Relationship::Cardinality

Constants

N = Cardinality::N

Attributes

destination	[R]	The destination entity. It corresponds to the model that has defined a `belongs_to` association with the other model.
domain	[R]	The domain in which this relationship is defined.
source	[R]	The source entity. It corresponds to the model that has defined a `has_one` or `has_many` association with the other model.

Public instance methods

associations ()

Returns all Active Record association objects that describe this relationship.

[show source]

# File lib/rails_erd/domain/relationship.rb, line 73
      def associations
        @forward_associations + @reverse_associations
      end

cardinality ()

Returns the cardinality of this relationship.

[show source]

# File lib/rails_erd/domain/relationship.rb, line 78
      def cardinality
        @cardinality ||= begin
          reverse_max = any_habtm?(associations) ? N : 1
          forward_range = associations_range(@forward_associations, N)
          reverse_range = associations_range(@reverse_associations, reverse_max)
          Cardinality.new(reverse_range, forward_range)
        end
      end

indirect? ()

Indicates if a relationship is indirect, that is, if it is defined through other relationships. Indirect relationships are created in Rails with has_many :through or has_one :through association macros.

[show source]

# File lib/rails_erd/domain/relationship.rb, line 91
      def indirect?
        !@forward_associations.empty? and @forward_associations.all?(&:through_reflection)
      end

many_to? ()

Indicates whether the source cardinality class of this relationship is equal to infinity. This is true for many-to-many relationships only.

[show source]

# File lib/rails_erd/domain/relationship.rb, line 129
      def many_to?
        cardinality.cardinality_class[0] != 1
      end

mutual? ()

Indicates whether or not the relationship is defined by two inverse associations (e.g. a has_many and a corresponding belongs_to association).

[show source]

# File lib/rails_erd/domain/relationship.rb, line 98
      def mutual?
        @forward_associations.any? and @reverse_associations.any?
      end

one_to? ()

Indicates whether the source cardinality class of this relationship is equal to one. This is true for one-to-one or one-to-many relationships only.

[show source]

# File lib/rails_erd/domain/relationship.rb, line 123
      def one_to?
        cardinality.cardinality_class[0] == 1
      end

recursive? ()

Indicates whether or not this relationship connects an entity with itself.

[show source]

# File lib/rails_erd/domain/relationship.rb, line 103
      def recursive?
        @source == @destination
      end

strength ()

The strength of a relationship is equal to the number of associations that describe it.

[show source]

# File lib/rails_erd/domain/relationship.rb, line 135
      def strength
        if source.generalized? then 1 else associations.size end
      end

to_many? ()

Indicates whether the destination cardinality class of this relationship is equal to infinity. This is true for one-to-many or many-to-many relationships only.

[show source]

# File lib/rails_erd/domain/relationship.rb, line 116
      def to_many?
        cardinality.cardinality_class[1] != 1
      end

to_one? ()

Indicates whether the destination cardinality class of this relationship is equal to one. This is true for one-to-one relationships only.

[show source]

# File lib/rails_erd/domain/relationship.rb, line 109
      def to_one?
        cardinality.cardinality_class[1] == 1
      end