Dynamic Discovery of Incomplete Information in XML Data

XML becomes widely used in Web applications and Database systems. XML also is an important medium in pervasive computing. While, XML data may contain incomplete information as its own characters which are tree type structure, different schemas in heterogeneous databases and non-standard operations of normal users. This incomplete information can bring some unexpected effectives in operations like SELECT, JION and etc. Although these problems are widely studied in relational database systems, this is not the case in the native XML database systems. So how to discover incomplete information and complete it becomes the main point of our research. In this paper, we extend the concept of XML data tree, which allows XML data contains incomplete information legally. Then we present an algorithm, DiscoveryFD, for efficient discovery of functional dependencies which are related with incomplete information in XML data. We also present an algorithm, XMLChase, which can help us complete the incomplete information.