activerecord - Rails: How to make has_many :through association work with Single Table Inheritance -

so in current project have article model can have different kinds of transactions. has 1 main transaction, under circumstances can have multiple sub-transactions.

until set this:

class article < activerecord::base   has_one :transaction, inverse_of: :article   has_many :partial_transactions, through: :transaction, source_type: 'multiplefixedpricetransaction', source: 'partialfixedpricetransaction', inverse_of: :articles end  class transaction < activerecord::base   belongs_to :article, inverse_of: :transaction # gets inherited kinds of transaction subclasses end  class multiplefixedpricetransaction < transaction   has_many :children, class_name: 'partialfixedpricetransaction', foreign_key: 'parent_id', inverse_of: :parent end  class partialfixedpricetransaction < transaction   belongs_to :parent, class_name: 'multiplefixedpricetransaction', inverse_of: :children   belongs_to :article, inverse_of: :partial_transactions # overwriting inheritance end 

now set errors like

activerecord::reflection::throughreflection#foreign_key delegated source_reflection.foreign_key, source_reflection nil:  #<activerecord::reflection::throughreflection:0x00000009bcc3f8 @macro=:has_many, @name=:partial_transactions, @options={:through=>:transaction, :source_type=>"multiplefixedpricetransaction", :source=>"partialfixedpricetransaction", :inverse_of=>:articles, :extend=>[]}, @active_record=article(id: integer ... 

by way, experimented lot source , source_type parameters , ones there examples. don't know them.

so, how can make work? how association set correctly?

thank you.