系统emp表恢复,该怎么解决

CREATE TABLE EMP       (EMPNO NUMBER(4) CONSTRAINT PK_EMP PRIMARY KEY,    ENAME VARCHAR2(10),    JOB VARCHAR2(9),    MGR NUMBER(4),    HIREDATE DATE,    SAL NUMBER(7,2),    COMM NUMBER(7,2),    DEPTNO NUMBER(2) CONSTRAINT FK_DEPTNO REFERENCES DEPT);INSERT INTO DEPT VALUES    (10,'ACCOUNTING','NEW YORK');INSERT INTO DEPT VALUES (20,'RESEARCH','DALLAS');INSERT INTO DEPT VALUES    (30,'SALES','CHICAGO');INSERT INTO DEPT VALUES    (40,'OPERATIONS','BOSTON');INSERT INTO EMP VALUES(7369,'SMITH','CLERK',7902,to_date('17-12-1980','dd-mm-yyyy'),800,NULL,20);INSERT INTO EMP VALUES(7499,'ALLEN','SALESMAN',7698,to_date('20-2-1981','dd-mm-yyyy'),1600,300,30);INSERT INTO EMP VALUES(7521,'WARD','SALESMAN',7698,to_date('22-2-1981','dd-mm-yyyy'),1250,500,30);INSERT INTO EMP VALUES(7566,'JONES','MANAGER',7839,to_date('2-4-1981','dd-mm-yyyy'),2975,NULL,20);INSERT INTO EMP VALUES(7654,'MARTIN','SALESMAN',7698,to_date('28-9-1981','dd-mm-yyyy'),1250,1400,30);INSERT INTO EMP VALUES(7698,'BLAKE','MANAGER',7839,to_date('1-5-1981','dd-mm-yyyy'),2850,NULL,30);INSERT INTO EMP VALUES(7782,'CLARK','MANAGER',7839,to_date('9-6-1981','dd-mm-yyyy'),2450,NULL,10);INSERT INTO EMP VALUES(7788,'SCOTT','ANALYST',7566,to_date('13-JUL-87')-85,3000,NULL,20);INSERT INTO EMP VALUES(7839,'KING','PRESIDENT',NULL,to_date('17-11-1981','dd-mm-yyyy'),5000,NULL,10);INSERT INTO EMP VALUES(7844,'TURNER','SALESMAN',7698,to_date('8-9-1981','dd-mm-yyyy'),1500,0,30);INSERT INTO EMP VALUES(7876,'ADAMS','CLERK',7788,to_date('13-JUL-87')-51,1100,NULL,20);INSERT INTO EMP VALUES(7900,'JAMES','CLERK',7698,to_date('3-12-1981','dd-mm-yyyy'),950,NULL,30);INSERT INTO EMP VALUES(7902,'FORD','ANALYST',7566,to_date('3-12-1981','dd-mm-yyyy'),3000,NULL,20);INSERT INTO EMP VALUES(7934,'MILLER','CLERK',7782,to_date('23-1-1982','dd-mm-yyyy'),1300,NULL,10);