This paper presents a novel information sharing framework using Service-Oriented Database System (SODB) for service registry and repository that facilitates data integration. A SODB is a database architecture composed with reusable services to support searching, querying, deleting, and storing data. As SODB is organized in a service-oriented manner, SODB can be easily changed or maintained by reusing different services. Thus, it can be used to share information in the cloud. The Information Sharing System (ISS) component of the SODB employs domain ontology to share data sources. The domain ontology utilizes mathematical equivalence relations to map data sources into appropriate domain ontology. It also facilitates dynamic query composition across data sources. This paper also presents the design, implementation, and performance evaluation of the ISS component. Our implementation is based on a real application, the Arizona Healthcare Cost Containment System (AHCCCS). This application demonstrates that the ISS can facilitate complex information integration. Finally, this paper presents the performance of the ISS using WAPT (Web Application Testing) for Microsoft Windows XP, and the response time consistently fall in between 0.1 to 0.15 second for each request.