Many commercial database systems maintain histograms to summarize the contents of relations and permit the efficient estimation of query result sizes and the access plan cost. In spatial database syst
Onion-like Fullerenes were produced at high-temperature in vacuum. The morphology of the carbon nano onion-like fullerenes was examined and characterized by hig
The problem of long transactions is a significant problem in spatial database.The checkout mechanism and multi-version mechanism are two kind methods of solving