请教版主SQL问题 版主快点进来啊

选择题
1.student表增加一个性别sex字段的sql语句为[  ]
A.update student update性别 char(2)
B.add 性别 char(2)
C.update 性别 char(2)
D.alter table student add 性别 char(2)
2.对student表所有记录的score字段值重新设置为0的sql语句为[  ]
A.update student set score=0
B.alter table student set score=0
C.set @core=0
D.create student set score=0
3.一个表的主键最多可以有[  ]个
A.1
B.2
C.无限
D.3
4.定义Class表的NO字段的取值在0到10之间的sql语句为[  ]
A.alter table class CHECK (Credit_Hour between 0 an 10)
B.alter table class constraint CK CHECK(NO between 0 and 10)
C.alter table class add constraint CK CHECK(NO between 0 and 10)
D.alter table class add constraint CK CHECK(NO >0 AND NO<10)

[ 本帖最后由 mzero123 于 2009-8-27 19:36 编辑 ]