Query Method for Skycube on the Data Space Mixed by Numeric and Nominal Attributes
Zhongping Zhang, Yan Xia, Lining Li · Journal of Chinese Computer Systems · 2011
In recent years,the study of the skyline query on data space mixed by numeric and nominal attributes is only confined to proceed in a single space.However,there are many skyline queries demand for different sub-space in practical application.In order to satisfy the needs for different sub-space skyline queries,we combine with IPO-tree Search semi-materialization method and propose the concept of semi-materialization skycube.Moreover,algorithm SMS is presented to efficiently calculate the semi-materialization skycube by sharing the sub-space skyline result sets and the query conditions.Meanwhile,an index NNAS-tree,which can meet the needs of users' skyline queries online in any sub-space of data space mixed by numeric and nominal attributes,is designed to store semi-materialization skycube.Finally,comparing with the nave algorithm,which calculates the skycube by separately computing every sub-space skyline,our extensive performance evaluations comfirm the effectiveness of SMS.