ono i ▁pol yg ons ▁of ▁a ▁set ▁of ▁sites ▁and ▁perform ▁a ▁cluster ▁analysis ▁on ▁a ▁set ▁of ▁points . ▁ ▁Vector ▁spatial ▁data ▁such ▁as ▁points , ▁pol yl ines ▁and ▁pol yg ons ▁can ▁be ▁given ▁topological ▁attributes ▁that ▁allow ▁complex ▁networks ▁to ▁be ▁model led . ▁Network ▁analysis ▁engines ▁are ▁provided ▁to ▁answer ▁questions ▁such ▁as ▁find ▁the ▁short est ▁path ▁between ▁two ▁nodes ▁or ▁how ▁to ▁optimize ▁a ▁delivery ▁route ▁( the ▁trav elling ▁sales man ▁problem ). ▁A ▁topology ▁engine ▁can ▁be ▁configured ▁with ▁a ▁set ▁of ▁rules ▁that ▁define ▁how ▁topological ▁entities ▁interact ▁with ▁each ▁other ▁when ▁new ▁data ▁is ▁added ▁or ▁existing ▁data ▁edited . ▁ ▁Data ▁abstra ction ▁In ▁V MD S ▁all ▁data ▁is ▁presented ▁to ▁the ▁application ▁as ▁objects . ▁This ▁is ▁different ▁from ▁many ▁rel ational ▁databases ▁that ▁present ▁the ▁data ▁as ▁rows ▁from ▁a ▁table ▁or ▁query ▁result ▁using ▁say ▁J DBC . ▁V MD S ▁provides ▁a ▁data ▁mod elling ▁tool ▁and ▁underlying ▁infrastr ucture ▁as ▁part ▁of ▁the ▁Small world ▁technology ▁platform ▁that ▁allows ▁administr ators ▁to ▁associate ▁a ▁table ▁in ▁the ▁database ▁with ▁a ▁Mag ik ▁exempl ar ▁( or ▁class ). ▁Mag ik ▁get ▁and ▁set ▁methods ▁for ▁the ▁Mag ik ▁exempl ar ▁can ▁be ▁automatically ▁generated ▁that ▁expose ▁a ▁table ' s ▁field ▁( or ▁column ). ▁Each ▁V MD S ▁row ▁manifest s ▁itself ▁to ▁the ▁application ▁as ▁an ▁instance ▁of ▁a ▁Mag ik ▁object ▁and ▁is ▁known ▁as ▁an ▁R W O ▁(