In this paper, we present a case study on the design of a web-based online service delivery system using IBM's Net.Commerce system as well as the lessons learned in completing this project. The design specification is presented using the UML notation, while database schema is presented using the IDEF1X notation. Our design specification includes architecture, system components using package diagrams, system functions using use case diagrams, their processing logic using activity diagrams, and database design. We present a detailed database design and comment on design and customization considerations specific to e-commerce systems. Our experience shows that e-commerce tools still lack certain functionality such as processing back orders, allowing for customizable returns, and sending email notification to users, but overall can speed up the development of the system. Understanding the structure and transaction processing of e-commerce database systems will help system designers effectively develop and maintain these systems. Readers of this paper will understand and learn a typical design specification of a web-based service delivery system and various technical design issues.