DATA QUERY SYSTEM OF GML SPATIAL DATABASEBASED ON EXPANDED NXD
Lan Xiaoji 1） ; Xiao Huihui 1） ; and Duan Yanming 2）
1)School of Construction and Mapping of Jiangxi Technical University,Ganzhou 3410002)School of Information and Science of Jiangxi Technical University,Ganzhou 341000
Abstract Currently, Geography Markup Language(GML) has become actually the international standard language for spatial data encoding, transmission, storage and release. Traditional query languages such as SQL and SQL extension , however, are not suitable for direct inquiry and updating of GML documents. Even the effective approaches working well with eXtensible Markup Language (XML) can not guarantee good results when applied to GML documents,for example, the W3C XQuery is a powerful standard query language for XML，but it does not support querying spatial features which includes the most important components in GML documents. We put forward the expansions of Inquiry of XQuery and space XQuery syntax, and to some extent, realize the data query of GML spatial database based on the expansion of Native XML Database(NXD).
