QUERY: CREATE VIEW street AS
   SELECT r.name, r.thepath, c.cname AS cname
   FROM road r, real_city c
   WHERE c.outline ## r.thepath;
QUERY: CREATE VIEW iexit AS
   SELECT ih.name, ih.thepath,
	interpt_pp(ih.thepath, r.thepath) AS exit
   FROM ihighway ih, ramp r
   WHERE ih.thepath ## r.thepath;
QUERY: CREATE VIEW toyemp AS
   SELECT name, age, location, 12*salary AS annualsal
   FROM emp;
