A.declare @abc int B.select * from grade C.create database sti D.delete * from grade
A.主鍵約束和唯一約束B.主鍵約束和外鍵約束C.唯一約束和外鍵約束D.以上都不是
A.唯一性索引 B.非聚集索引 C.聚集索引 D.外鍵索引