66 lines
2.1 KiB
Ruby
66 lines
2.1 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
# Add support for writing recursive CTEs in ActiveRecord
|
|
|
|
# Initially from Lorin Thwaits (https://github.com/lorint) as per comment:
|
|
# https://github.com/vlado/activerecord-cte/issues/16#issuecomment-1433043310
|
|
|
|
# Modified from the above code to change the signature to
|
|
# `with_recursive(hash)` and extending CTE hash values to also includes arrays
|
|
# of values that get turned into UNION ALL expressions.
|
|
|
|
# This implementation has been merged in Rails: https://github.com/rails/rails/pull/51601
|
|
|
|
module ActiveRecord
|
|
module QueryMethodsExtensions
|
|
def with_recursive(*args)
|
|
@with_is_recursive = true
|
|
check_if_method_has_arguments!(__callee__, args)
|
|
spawn.with_recursive!(*args)
|
|
end
|
|
|
|
# Like #with_recursive but modifies the relation in place.
|
|
def with_recursive!(*args) # :nodoc:
|
|
self.with_values += args
|
|
@with_is_recursive = true
|
|
self
|
|
end
|
|
|
|
private
|
|
|
|
def build_with(arel)
|
|
return if with_values.empty?
|
|
|
|
with_statements = with_values.map do |with_value|
|
|
raise ArgumentError, "Unsupported argument type: #{with_value} #{with_value.class}" unless with_value.is_a?(Hash)
|
|
|
|
build_with_value_from_hash(with_value)
|
|
end
|
|
|
|
# Was: arel.with(with_statements)
|
|
@with_is_recursive ? arel.with(:recursive, with_statements) : arel.with(with_statements)
|
|
end
|
|
|
|
def build_with_value_from_hash(hash)
|
|
hash.map do |name, value|
|
|
Arel::Nodes::TableAlias.new(build_with_expression_from_value(value), name)
|
|
end
|
|
end
|
|
|
|
def build_with_expression_from_value(value)
|
|
case value
|
|
when Arel::Nodes::SqlLiteral then Arel::Nodes::Grouping.new(value)
|
|
when ActiveRecord::Relation then value.arel
|
|
when Arel::SelectManager then value
|
|
when Array then value.map { |e| build_with_expression_from_value(e) }.reduce { |result, value| Arel::Nodes::UnionAll.new(result, value) }
|
|
else
|
|
raise ArgumentError, "Unsupported argument type: `#{value}` #{value.class}"
|
|
end
|
|
end
|
|
end
|
|
end
|
|
|
|
ActiveSupport.on_load(:active_record) do
|
|
ActiveRecord::QueryMethods.prepend(ActiveRecord::QueryMethodsExtensions)
|
|
end
|