Class: AdjustableSchema::ActiveRecord::QueryMethods::WithChain

Inherits:
Object
  • Object
show all
Defined in:
lib/adjustable_schema/active_record/query_methods.rb

Instance Method Summary collapse

Constructor Details

#initialize(scope) ⇒ WithChain

Returns a new instance of WithChain.



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# File 'lib/adjustable_schema/active_record/query_methods.rb', line 5

def initialize scope
	@scope = scope
end

Instance Method Details

#recursive(*args) ⇒ Object

Returns a new relation expressing WITH RECURSIVE statement.

#recursive accepts conditions as a hash. See QueryMethods#with for more details on each format.

User.with.recursive(
  descendants: User.joins('INNER JOIN descendants ON users.parent_id = descendants.id')
)
# WITH RECURSIVE descendants AS (
#   SELECT * FROM users
#   UNION
#   SELECT * FROM users INNER JOIN descendants ON users.parent_id = descendants.id
# ) SELECT * FROM descendants

WARNING! Due to how Arel works,

* `recursive` can't be chained with any prior non-recursive calls to `with` and
* all subsequent non-recursive calls to `with` will be treated as recursive ones.



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# File 'lib/adjustable_schema/active_record/query_methods.rb', line 26

def recursive *args
	args.map! do
		next _1 unless _1.is_a? Hash

		_1
				.map(&method(:with_recursive_union))
				.to_h
	end

	case @scope.with_values
	in []
		@scope = @scope.with :recursive, *args
	in [ :recursive, * ]
		@scope = @scope.with *args
	else
		raise ArgumentError, "can't chain `WITH RECURSIVE` with non-recursive one"
	end

	@scope
end