【正文】
用alter table命令修改movies關(guān)系模式,增加引用完整性約束cproducerc,要求movies表中的producerC必須是在MovieExec表中已有的導(dǎo)演。四、 實(shí)驗(yàn)步驟用create database命令創(chuàng)建電影數(shù)據(jù)庫(以自己的學(xué)號(hào)命名)。end 。return next sum。end loop。beginfor ramloop in select ram from laptop loopsum :=sum + ramloop。ramloop int。 create function laptop() returns setof realas $$declare ramcount int :=0。⑧CREATE INDEX aindex ON StarsIn(StarName)。⑥CREATE VIEW StudioPress AS SELECT ,cert FROM MovieExec,Studio WHERE =。④ALTER TABLE movies ADD CONSTRAINT clength CHEAK(length=60 AND length=250)。②ALTER TABLE StarsIn ADD CONSTRAINT cmovies FOREIGN KEY(mov