inflowERP/app/models/so_sales_order.rb

class SoSalesOrder < InflowServer
  self.table_name = 'So_SalesOrder'
  self.primary_key = 'SalesOrderId'

  has_many :lines, class_name: "SoSalesOrderLine", foreign_key: "SalesOrderId", primary_key: "SalesOrderId"
end