Double Entry Expenses Accounting System in PHP

Basing on the accounting basic equation and expanded equations reformed in 1993, the paper synthesizes the primary viewpoints about accounting equations system reconstruction, including the negation viewpoint on accounting expanded equations, the expansion viewpoint on accounting basic equation, the accounting equations system reconstruction viewpoint under private capital economy and reconstruction basing on behavioral accounting model etc. Through synthesis and comment of above viewpoints, this article constructs an accounting equations system including static accounting equation and dynamic accounting equations, thatpsilas ldquofinancial assets + knowledge assets = Creditorpsilas claim+financial capital ownerpsilas equity + Intellectual capital ownerpsilas equity", ldquo(Net) Income = Revenue - Expense" and ldquofinancial assets + Knowledge assets = creditorpsilas claim + Financial capital ownerpsilas equity + Intellectual capital ownerpsilas equity + profit or loss ". The equations system forms the core theory of double entry bookkeeping which is suitable to the contemporary economy.