Research On Query Algorithm Based On MOIS-Tree

In recent years,with the development of information technology,the research of spatial database has made great progress.Nearest neighbor,furthest neighbor,direction and distance query spatial query algorithm is the main research direction of spatial database query algorithm.But the family trees,based on R-tree,R*-tree,R+-tree,have some inevitable shortcomings,namely to access more data nodesin the process of query,so increasing the burden of disk I/O.In this paper,MOIS-tree is adopted as the storage structure of the query,which is a kind of index structure based on order relation.In the process of the query,it has a very efficient pruning effect,lower nodes access number.This paper,the farthest neighbor query,direction and distance of the query algorithms are studied by taking MOIS-tree as storage tructure.In this paper,the updating algorithms of data insertion and deletion of the MOIS-tree index structure are designed.the furthest neighbor query based on index of MOIS-tree structure as well as the direction and distance query problem carried on the thorough careful research.Specific work was done as follows:First,data update algorithmsfor MOIS-tree are given,including the data in the data insertion and deletion algorithm overflow and underflow,the processing method,namely,merging and splitting method respectively.Secondly,in the furthest neighbor query,the minimum maximum distance(Min Max Dist)and maximum distance(Max Dist)are defined,and according to the position relation of MOIS-tree nodes to calculate Min Max Dist and Max Dist,and pruning to Min Max Dist Max Dist,so that the furthest neighbor query algorithm is provided.The analysis for time complexity of the algorithm is presented.Thirdly,in the query algorithm of direction and distance,the query modelis given according to the relation between the direction and distance.Meanwhile,the detailed analysis of the position relation between the querypoint and the position relations of fan-shaped area is made when the directional query is processed,andthejudgment theorems corresponding cases are given.By them,the pruning rules for the corresponding queries are presented and the direction and distance query algorithm is obtained.The correctness and termination of the algorithm is proved.Finally,the experimental results are respectively given for the furthest neighbor query and the directional and distance query to show the new algorithm's efficiency.