Query Optimization in Object Oriented Databases Based on SD-Tree and n-ary Tree

In this paper, we suggest a new technique to create index helping to query almost identical similarities with keywords in case there is no correct match found. It is based on a SD-Tree and a n-ary Tree helping to query related information when there is no correct match. Index structure arranges signatures according to hierarchical clustering for improving assessment of query. This method is based on technique of using signature file and SD-Tree and signature files are organized according to decentralization to filter unsuitable data quickly and each signature file is saved according to SD-Tree structure for increasing speed of scanning signature. This method helps to decrease effectively search space, so therefore improving effectively complexity of query time.