Data Integration in Multi-sources Information Systems

Data integration involves combining data coming from different sources and providing users with a unified view of these data. In this paper, we introduced the problem of integration of multi-source information systems with some focus on the heterogeneity and conflict issues at different levels .We have made some survey related the current implementations methods that have been used to solve the problems of data integration of multi sources IS which can be classified on three will established approaches, we have also discussed some of the limitations and advantages of such approaches, next we talked about the current trends in data integration such as warehousing, descriptive logic and ontology . Finally, we have presented some case studies that have been implemented using some of these approaches