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SQL> CREATE OR REPLACE NOFORCE VIEW EMP_VIEW20
  2  AS
  3  SELECT EMPNO, ENAME, DEPTNO
  4  FROM EM01
  5  WHERE DEPTNO = 20;

View created.

SQL> SELECT * FROM EMP_VIEW20;

     EMPNO ENAME          DEPTNO
---------- ---------- ----------
      7566 JONES              20
      7902 FORD               20
      7368 SMITH              20
      7788 SCOTT              20
      7369 SMITH              20
      7876 ADAMS              20

6 rows selected.

SQL> UPDATE EMP_VIEW20 SET ENAME = 'TEST' WHERE EMPNO = 7369;

1 row updated.

SQL> SELECT * FROM EMP_VIEW20;

     EMPNO ENAME          DEPTNO
---------- ---------- ----------
      7566 JONES              20
      7902 FORD               20
      7368 SMITH              20
      7788 SCOTT              20
      7369 TEST               20
      7876 ADAMS              20

6 rows selected.

SQL> UPDATE EMP_VIEW20 SET DEPTNO = 40 WHERE EMPNO = 7369;

1 row updated.

SQL> SELECT * FROM EMP_VIEW20;

     EMPNO ENAME          DEPTNO
---------- ---------- ----------
      7566 JONES              20
      7902 FORD               20
      7368 SMITH              20
      7788 SCOTT              20
      7876 ADAMS              20

SQL> SELECT * FROM EM01;

     EMPNO ENAME      JOB              MGR HIREDATE            SAL       COMM       DEPTNO
---------- ---------- --------- ---------- ------------ ---------- ----------   ----------
      7654 MARTIN     SALESMAN        7698 28-SEP-81          1250       1400        30
      7566 JONES      MANAGER         7839 02-APR-81          2975                      20
      7844 TURNER     SALESMAN        7698 08-SEP-98          1500          0        30
      7900 JAMES      CLERK           7698 03-NOV-81          1957                       30
      7369 TEST       CLERK           7902 17-NOV-80           800        40
      7876 ADAMS      CLERK           7788 12-JAN-83          1100                        20

SQL> CREATE OR REPLACE NOFORCE VIEW EMP_VIEW20
  2  AS
  3  SELECT EMPNO, ENAME, DEPTNO
  4  FROM EM01
  5  WHERE DEPTNO = 20 WITH CHECK OPTION
  6 ; 

View created.

SQL> SELECT VIEW_NAME, TEXT FROM USER_VIEWS;

VIEW_NAME                              TEXT
------------------------------  ------------------------------------------
VIEW_EMPLOYEES                     SELECT *
                                                 FROM EMPLOYEES
-------------------------------------------------------------------------
EMP_VIEW20                              SELECT EMPNO, ENAME, DEPTNO
                                                FROM EM01
                                                WHERE DEPTNO = 20 WITH CHECK OPTION
-------------------------------------------------------------------------
CHECK_OPTION                         SELECT empno, ename, deptno, job
                                                       FROM  emp_test3
                                                       WHERE deptno = 10

-- 사원의 이름을 변경하는것은 가능함.
SQL> UPDATE EMP_VIEW20
  2  SET ENAME = 'TEST3'
  3  WHERE EMPNO = 7876;

1 row updated.

-- 부서 번호가 뷰를 생성할때 WHERE 절에 사용된 컬럼이므로 다음과 같이 WITH CHECK OPTION 이 지정된 뷰에 대해서 부서번호 값을 변경하려고 접근하면 에러가 발생함.
SQL> UPDATE EMP_VIEW20
  2  SET DEPTNO = 40
  3  WHERE EMPNO = 7876;
UPDATE EMP_VIEW20
       *
ERROR at line 1:
ORA-01402: view WITH CHECK OPTION where-clause violation


SQL> SELECT * FROM EMP_VIEW20;

     EMPNO ENAME          DEPTNO
---------- ---------- ----------
      7566 JONES              20
      7902 FORD               20
      7368 SMITH              20
      7788 SCOTT              20
      7876 TEST3              20

SQL> CREATE OR REPLACE NOFORCE VIEW EMP_VIEW20
  2  AS
  3  SELECT EMPNO, ENAME, DEPTNO
  4  FROM EM01
  5  WHERE DEPTNO = 20 WITH READ ONLY
  6  ;

View created.

SQL> UPDATE EMP_VIEW20
  2  SET ENAME = 'TEST5'
  3  WHERE EMPNO = 7876;
SET ENAME = 'TEST5'
    *
ERROR at line 2:
ORA-01733: virtual column not allowed here (가상 열은 사용할 수 없습니다.)

SQL> DESC EMPLOYEES;
ERROR:
ORA-04043: object EMPLOYEES does not exist


SQL> CREATE OR REPLACE VIEW VIEW_EMPLOYEES
  2  AS
  3  SELECT *  
  4  FROM EMPLOYEES;
FROM EMPLOYEES
     *
ERROR at line 4:
ORA-00942: table or view does not exist


SQL> CREATE OR REPLACE FORCE VIEW VIEW_EMPLOYEES
  2  AS
  3  SELECT *
  4  FROM EMPLOYEES;

Warning: View created with compilation errors.

-- 경고는 발생하지만 뷰가 생성되었다는 메시지를 출력합니다.
-- 생성된 뷰를 데이터 딕셔너리인 USER_VIEWS를 통해서 검색할수 있습니다.
SQL> SELECT VIEW_NAME, TEXT FROM USER_VIEWS;

VIEW_NAME                      TEXT
------------------------- ------------------------------------
VIEW_EMPLOYEES            SELECT *
                                        FROM EMPLOYEES
--------------------------------------------------------------
CHECK_OPTION                 SELECT empno, ename, deptno, job
                                              FROM  emp_test3
                                             WHERE deptno = 10
SQL>