A semi-automatic approach for WSC

Web service composition helps to complete software development projects on the basis of reusability. Most web service composition approaches tend to be either practical and lacking formal models, or formal and lacking practical aspects. This paper proposes a novel approach for semi-automatic web service composition to close the gap between formal models and database practice. In this approach, the web service is modeled in G-net and then stored in a database. Web service composition can then be obtained using SQL queries and relational algebra operators. A Java-based tool for web service composition is developed based on relational algebra operators. The proposed approach is demonstrated using a digital class assistant as a case study.