For centuries accounting was the only formal information system in existence for business enterprises. Now accounting is often only a small part of an integrated information system. While numerous attempts have been made to clarify the exact structure of accounting, they have all been encumbered by past traditions that, while optimal under manual methods, did not do justice to accounting in a database environment. This paper shows how an informal model of accounting as movement of sand in a sandbox can be mapped to an ontologically complete financial accounting information system. Finally, the new model is contrasted with three competing models, and its implications for design and use of accounting information systems are discussed.