Abstract. Database systems (DBSs) can play an essential role in facilitating the query and cache management in context-aware mobile information systems (CAMIS). Two of the fundamental aspects of such management are update notifications and context-aware query processing. Unfortunately, DBSs does not provide a built-in update notification function and are not aware of the context of their usage. This paper presents an XML model called XReAl (XML-based Relational Algebra) that assists DBSs in extending their capabilities to support context-aware queries and cache management for mobile environments.