血间数据库奥例 select Boundary. id-contour, x, y from Country, Boundary, Contour, Point where name= France and Country. id-boundary=Boundary. id-boundary and Boundary. id-contour=Contour. id-contour and Contour. id-point=Point. id-point order by boundary. id-contour point-nmum;空间数据库实例 select Boundary.id-contour,x,y from Country,Boundary,Contour,Point where name=‘France’ and Country.id-boundary=Boundary.id-boundary and Boundary.id-contour=Contour.id-contour and Contour.id-point=Point.id-point order by Boundary.id-contour,point-num ；