数据库（oracle的安全性和完整性控制）

1.create user s2015214068u1 identified by 123456;create user s2015214068u2 identified by 123456;create user s2015214068u3 identified by 123456;create user s2015214068u4 identified by 123456;grant connect to s2015214068u1,s2015214068u2,s2015214068u3,s2015214068u4;2.grant select on student to s2015214068u1;切换用户1）select * from s2015214068.student;2）select sname,sno,ssex from s2015214068.student where sname like '张%';3）select sname,sno from s2015214068.student where sname like '.阳';show user;/*显示用户名*/3.grant all on student  to s2015214068u2,s2015214068u3;grant all on course  to s2015214068u2,s2015214068u3;update  s2015214068.student  set sage=20 where sname='smith';4.grant update(sno) on student to s2015214068u4;update  s2015214068.student  set sno='201521406' where sname='smith';5.先创建u5用户create user s2015214068u5 identified by 123456;grant insert on sc to s2015214068u5;insert into s2015214068.sc values('200215122','1',90);6.grant select on sc to public;1)select sno,grade from s2015214068.sc where cno='3' order by sno desc;2)select cno,count(sno) from s2015214068.sc group by cno;二1.revoke update on student from s2015214068u2;2.revoke select on sc from public;3.revoke insert on sc from s2015214068u5;4.1.对于s2015214068u2用户，输入修改学号指令：update  s2015214068.student  set sno='201521406' where sname='smith';提示：SQL 错误: ORA-01031: 权限不足2.提示：表或视图不存在3.提示：表或视图不存在三1.create role gp;2.grant select,update,insert on student to gp;3.grant gp to s2015214068u1;4.登录s2015214068u1均具有相应权限四：1.create table Teacher(Tno varchar(9) primary key,Tname varchar(9) unique);2.create table Student(Sno varchar(4) check(sno between 9000 and 9999),sage int constraint a1 check  (sage<29),ssex varchar(2) check (ssex in('男','女') ),sname varchar(10) not null);3. alter table Student drop constraint a1; alter table Student add constraint a1 check(sage<40);4.
4.create table course1(cno varchar2(4) constraint pk_c primary key,cname varchar2(10),tno varchar2(10) constraint fk_c_t references teacher(tno) On Delete Set NULL,credit number(3) check (credit<=7));5.create table sc1(cno varchar2(4) REFERENCES course1(cno) On Delete Cascade,sno char(10)REFERENCES stu(sno) On Delete Cascade,grade number(3),primary key(cno,sno));