REA (Resource-Event-Agent) is a design pattern for building agile enterprise systems that are centered on the give and take nature of accounting events. REA systems preserve the raw transaction details, enabling retrieval of data to support financial and managerial accounting decisions and also to support management, marketing, and many other non-accounting business decisions. REA allows enterprises to capture historical details of what has happened, and enables integration of enterprise policies (what could or should happen) and commitments (what is scheduled to happen). REA enables understanding of the enterprise and its value system, value chain, and business processes to know what questions are important to ask for accounting analytics. REA also facilitates query building to answer those important questions.