Oracle数据库（九）数据库对象

SQL> --视图
SQL> create view empinfoview2  as3  select e.empno,e.ename,e.sal,e.sal*12 annsal,d.dname4  from emp e,dept d5  where e.deptno=d.deptno;
create view empinfoview*
第 1 行出现错误: 
ORA-01031: 权限不足 SQL> /视图已创建。SQL> desc empinfoview名称                                      是否为空? 类型----------------------------------------- -------- ----------------------------EMPNO                                     NOT NULL NUMBER(4)ENAME                                              VARCHAR2(10)SAL                                                NUMBER(7,2)ANNSAL                                             NUMBERDNAME                                              VARCHAR2(14)SQL> select * from empinfoview;EMPNO ENAME             SAL     ANNSAL DNAME                               
---------- ---------- ---------- ---------- --------------                      7369 SMITH             800       9600 RESEARCH                            7499 ALLEN            1600      19200 SALES                               7521 WARD             1250      15000 SALES                               7566 JONES            2975      35700 RESEARCH                            7654 MARTIN           1250      15000 SALES                               7698 BLAKE            2850      34200 SALES                               7782 CLARK            2450      29400 ACCOUNTING                          7788 SCOTT            3000      36000 RESEARCH                            7839 KING             5000      60000 ACCOUNTING                          7844 TURNER           1500      18000 SALES                               7876 ADAMS            1100      13200 RESEARCH                            EMPNO ENAME             SAL     ANNSAL DNAME                               
---------- ---------- ---------- ---------- --------------                      7900 JAMES             950      11400 SALES                               7902 FORD             3000      36000 RESEARCH                            7934 MILLER           1300      15600 ACCOUNTING                          已选择 14 行。SQL> create or replace view empinfoview2  as3  select e.empno,e.ename,e.sal,e.sal*12 annsal,d.dname4  from emp e,dept d5  where e.deptno=d.deptno6  with read only;视图已创建。SQL> --with check option 只能操作看得到的部分
SQL> host clSQL> host clsSQL> --序列
SQL> --sequence
SQL> create sequence myseq;序列已创建。SQL> create table testseq2  (tid number,3   tname varchar2(20));表已创建。SQL> select myseq.currval from dual;
select myseq.currval from dual*
第 1 行出现错误: 
ORA-08002: 序列 MYSEQ.CURRVAL 尚未在此会话中定义 SQL> select myseq.nextval from dual;NEXTVAL                                                                      
----------                                                                      1                                                                      已选择 1 行。SQL> select myseq.currval from dual;CURRVAL                                                                      
----------                                                                      1                                                                      已选择 1 行。SQL> -- insert into testseq(tid,tname) values(?,?);
SQL> insert into testseq(tid,tname) values(myseq.nextval,'aaa');已创建 1 行。SQL> /已创建 1 行。SQL> /已创建 1 行。SQL> /已创建 1 行。SQL> select * from testseq;TID TNAME                                                                
---------- --------------------                                                 2 aaa                                                                  3 aaa                                                                  4 aaa                                                                  5 aaa                                                                  已选择 4 行。SQL> commit;提交完成。SQL> insert into testseq(tid,tname) values(myseq.nextval,'aaa');已创建 1 行。SQL> /已创建 1 行。SQL> rollback;回退已完成。SQL> insert into testseq(tid,tname) values(myseq.nextval,'aaa');已创建 1 行。SQL> select * from testseq;TID TNAME                                                                
---------- --------------------                                                 2 aaa                                                                  3 aaa                                                                  4 aaa                                                                  5 aaa                                                                  8 aaa                                                                  已选择 5 行。SQL> host clsSQL> --索引 index
SQL> create index myindex2  on emp(deptno);索引已创建。SQL> --同义词(别名)：代表：表，视图，存储过程*****
SQL> show user
USER 为 "SCOTT"
SQL> select count(*) from hr.employees;
select count(*) from hr.employees*
第 1 行出现错误: 
ORA-00942: 表或视图不存在 SQL> select count(*) from hr.employees;COUNT(*)                                                                      
----------                                                                      107                                                                      已选择 1 行。SQL> --为hr.employees起别名 ---> 同义词
SQL> create synonym hremp for hr.employees;
create synonym hremp for hr.employees
*
第 1 行出现错误: 
ORA-01031: 权限不足 SQL> /同义词已创建。SQL> select count(*) from hremp;COUNT(*)                                                                      
----------                                                                      107                                                                      已选择 1 行。SQL> spool oe\