A rule-based approach to Web-based application development

Common design patterns in application development mix implementation of business logic with application logic, user interface logic, or with data access logic. This leads to results that business logic is not well maintainable and reusable, the application code should be reimplemented each time the business logic has changed or the same business logic should be reimplemented for each application. This paper presents a new rule-based approach to Web-based IS development making possible separating the business logic from interface or application logic when creating complex Web-based software applications. The technology consists of 2 main parts: the application server Xstone for creating 3-layered systems and the RqlGandalf rule solver. The middleware server Xstone connects to Oracle, PostgreSQL databases and the Rql rule system. The Rql rule system is targeted for defining and using business logic rules. The Rql rule system is able to read data from a SQL database: it can call the application server and import/convert SQL-given data into its own knowledge base. The presented rule-based system development technology is implemented for the Linux platform as open source software.