Class: RareMap::Relation

Inherits:
Object
  • Object
show all
Includes:
Errors
Defined in:
lib/rare_map/relation.rb

Overview

RareMap::Relation defines one of has_one, has_many and has_many_through relations of a database table.

Author:

  • Wei-Ming Wu

Constant Summary collapse

HAS_ONE =

The :has_one association.

:has_one
BELONGS_TO =

The :belongs_to association.

:belongs_to
HAS_MANY =

The :has_many association.

:has_many
HAS_MANY_THROUGH =

The :has_many_through association.

:has_many_through
RELATIONS =

All three kinds of relations

[HAS_ONE, BELONGS_TO, HAS_MANY, HAS_MANY_THROUGH]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(type, foreign_key, table, through = nil) ⇒ Relation

Creates a Relation.

Parameters:

  • type (Symbol) —

    the type, :has_one or :has_many or :has_many_through

  • foreign_key (String) —

    the foreign key of this Relation based on

  • table (String) —

    the table of this Relation refers to

  • through (String, nil) (defaults to: nil) —

    the table of this Relation goes through

Raises:



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# File 'lib/rare_map/relation.rb', line 36

def initialize(type, foreign_key, table, through = nil)
  raise RelationNotDefinedError, 'Relation type not defined.' unless RELATIONS.include? type
  @type, @foreign_key, @table, @through = type, foreign_key, table, through
end

Instance Attribute Details

#foreign_key ⇒ String (readonly)

Returns the foreign key of this Relation based on.

Returns:

  • (String) —

    the foreign key of this Relation based on



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# File 'lib/rare_map/relation.rb', line 15

class Relation
  # The :has_one association.
  HAS_ONE = :has_one
  # The :belongs_to association.
  BELONGS_TO = :belongs_to
  # The :has_many association.
  HAS_MANY = :has_many
  # The :has_many_through association.
  HAS_MANY_THROUGH = :has_many_through
  # All three kinds of relations
  RELATIONS = [HAS_ONE, BELONGS_TO, HAS_MANY, HAS_MANY_THROUGH]
  include Errors
  attr_reader :type, :foreign_key, :table, :through
  
  # Creates a Relation.
  #
  # @param type [Symbol] the type, `:has_one` or `:has_many` or `:has_many_through`
  # @param foreign_key [String] the foreign key of this Relation based on
  # @param table [String] the table of this Relation refers to
  # @param through [String, nil] the table of this Relation goes through
  # @return [Relation] the Relation object
  def initialize(type, foreign_key, table, through = nil)
    raise RelationNotDefinedError, 'Relation type not defined.' unless RELATIONS.include? type
    @type, @foreign_key, @table, @through = type, foreign_key, table, through
  end
end

#table ⇒ String (readonly)

Returns the table of this Relation refers to.

Returns:

  • (String) —

    the table of this Relation refers to



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# File 'lib/rare_map/relation.rb', line 15

class Relation
  # The :has_one association.
  HAS_ONE = :has_one
  # The :belongs_to association.
  BELONGS_TO = :belongs_to
  # The :has_many association.
  HAS_MANY = :has_many
  # The :has_many_through association.
  HAS_MANY_THROUGH = :has_many_through
  # All three kinds of relations
  RELATIONS = [HAS_ONE, BELONGS_TO, HAS_MANY, HAS_MANY_THROUGH]
  include Errors
  attr_reader :type, :foreign_key, :table, :through
  
  # Creates a Relation.
  #
  # @param type [Symbol] the type, `:has_one` or `:has_many` or `:has_many_through`
  # @param foreign_key [String] the foreign key of this Relation based on
  # @param table [String] the table of this Relation refers to
  # @param through [String, nil] the table of this Relation goes through
  # @return [Relation] the Relation object
  def initialize(type, foreign_key, table, through = nil)
    raise RelationNotDefinedError, 'Relation type not defined.' unless RELATIONS.include? type
    @type, @foreign_key, @table, @through = type, foreign_key, table, through
  end
end

#through ⇒ String? (readonly)

Returns the table of this Relation goes through.

Returns:

  • (String, nil) —

    the table of this Relation goes through



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# File 'lib/rare_map/relation.rb', line 15

class Relation
  # The :has_one association.
  HAS_ONE = :has_one
  # The :belongs_to association.
  BELONGS_TO = :belongs_to
  # The :has_many association.
  HAS_MANY = :has_many
  # The :has_many_through association.
  HAS_MANY_THROUGH = :has_many_through
  # All three kinds of relations
  RELATIONS = [HAS_ONE, BELONGS_TO, HAS_MANY, HAS_MANY_THROUGH]
  include Errors
  attr_reader :type, :foreign_key, :table, :through
  
  # Creates a Relation.
  #
  # @param type [Symbol] the type, `:has_one` or `:has_many` or `:has_many_through`
  # @param foreign_key [String] the foreign key of this Relation based on
  # @param table [String] the table of this Relation refers to
  # @param through [String, nil] the table of this Relation goes through
  # @return [Relation] the Relation object
  def initialize(type, foreign_key, table, through = nil)
    raise RelationNotDefinedError, 'Relation type not defined.' unless RELATIONS.include? type
    @type, @foreign_key, @table, @through = type, foreign_key, table, through
  end
end

#type ⇒ Symbol (readonly)

Returns the type of relation, :has_one or :has_many or :has_many_through.

Returns:

  • (Symbol) —

    the type of relation, :has_one or :has_many or :has_many_through



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# File 'lib/rare_map/relation.rb', line 15

class Relation
  # The :has_one association.
  HAS_ONE = :has_one
  # The :belongs_to association.
  BELONGS_TO = :belongs_to
  # The :has_many association.
  HAS_MANY = :has_many
  # The :has_many_through association.
  HAS_MANY_THROUGH = :has_many_through
  # All three kinds of relations
  RELATIONS = [HAS_ONE, BELONGS_TO, HAS_MANY, HAS_MANY_THROUGH]
  include Errors
  attr_reader :type, :foreign_key, :table, :through
  
  # Creates a Relation.
  #
  # @param type [Symbol] the type, `:has_one` or `:has_many` or `:has_many_through`
  # @param foreign_key [String] the foreign key of this Relation based on
  # @param table [String] the table of this Relation refers to
  # @param through [String, nil] the table of this Relation goes through
  # @return [Relation] the Relation object
  def initialize(type, foreign_key, table, through = nil)
    raise RelationNotDefinedError, 'Relation type not defined.' unless RELATIONS.include? type
    @type, @foreign_key, @table, @through = type, foreign_key, table, through
  end
end