CREATE TABLE PAPERpno char6 PRIMARY KEY pna char10 ppr float;CREATE TABLE CUSTOMERcno char8 PRIMARY KEY cna char10 adr char20;CREATE TABLE CPcno char8 pno char6 num int PRIMARY KEYpnocno FOREIGN KEY

创建视图C_P_N： CREATE VIEW C_P_N AS SELECT c.cno, c.cna, p.pno, p.pna, cp.num FROM CUSTOMER c, PAPER p, CP cp WHERE c.cno = cp.cno AND p.pno = cp.pno;

修改视图C_P_N，使其含有报纸单价信息： ALTER VIEW C_P_N AS SELECT c.cno, c.cna, p.pno, p.pna, p.ppr, cp.num FROM CUSTOMER c, PAPER p, CP cp WHERE c.cno = cp.cno AND p.pno = cp.pno;