DROP TABLE SALGRADE;
DROP TABLE EMP;
DROP TABLE DEPT;

CREATE TABLE DEPT (
  DEPTNO NUMBER(2,0), 
  DNAME VARCHAR2(14), 
  LOC VARCHAR2(13)
) ;

CREATE TABLE EMP(
  EMPNO NUMBER(4,0), 
  ENAME VARCHAR2(10), 
  JOB VARCHAR2(9), 
  MGR NUMBER(4,0), 
  HIREDATE  DATE, 
  SAL NUMBER(7,2), 
  COMM NUMBER(7,2), 
  DEPTNO NUMBER(2,0)
);

CREATE TABLE SALGRADE (
  GRADE NUMBER, 
  LOSAL NUMBER, 
  HISAL NUMBER
) ;

Insert into DEPT (DEPTNO,DNAME,LOC) values (10,'ACCOUNTING','NEW YORK');
Insert into DEPT (DEPTNO,DNAME,LOC) values (20,'RESEARCH','DALLAS');
Insert into DEPT (DEPTNO,DNAME,LOC) values (30,'SALES','CHICAGO');
Insert into DEPT (DEPTNO,DNAME,LOC) values (40,'OPERATIONS','BOSTON');

Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7369,'SMITH','CLERK',7902,to_date('80/12/17','RR/MM/DD'),800,null,20);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7499,'ALLEN','SALESMAN',7698,to_date('81/02/20','RR/MM/DD'),1600,300,30);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7521,'WARD','SALESMAN',7698,to_date('81/02/22','RR/MM/DD'),1250,500,30);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7566,'JONES','MANAGER',7839,to_date('81/04/02','RR/MM/DD'),2975,null,20);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7654,'MARTIN','SALESMAN',7698,to_date('81/09/28','RR/MM/DD'),1250,1400,30);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7698,'BLAKE','MANAGER',7839,to_date('81/05/01','RR/MM/DD'),2850,null,30);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7782,'CLARK','MANAGER',7839,to_date('81/06/09','RR/MM/DD'),2450,null,10);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7839,'KING','PRESIDENT',null,to_date('81/11/17','RR/MM/DD'),5000,null,10);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7844,'TURNER','SALESMAN',7698,to_date('81/09/08','RR/MM/DD'),1500,0,30);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7900,'JAMES','CLERK',7698,to_date('81/12/03','RR/MM/DD'),950,null,30);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7902,'FORD','ANALYST',7566,to_date('81/12/03','RR/MM/DD'),3000,null,20);
Insert into EMP (EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO) values (7934,'MILLER','CLERK',7782,to_date('82/01/23','RR/MM/DD'),1300,null,10);

Insert into SALGRADE (GRADE,LOSAL,HISAL) values (1,700,1200);
Insert into SALGRADE (GRADE,LOSAL,HISAL) values (2,1201,1400);
Insert into SALGRADE (GRADE,LOSAL,HISAL) values (3,1401,2000);
Insert into SALGRADE (GRADE,LOSAL,HISAL) values (4,2001,3000);
Insert into SALGRADE (GRADE,LOSAL,HISAL) values (5,3001,9999);

ALTER TABLE EMP ADD CONSTRAINT PK_EMP PRIMARY KEY (EMPNO);

ALTER TABLE DEPT ADD CONSTRAINT PK_DEPT PRIMARY KEY (DEPTNO);

ALTER TABLE EMP ADD CONSTRAINT FK_DEPTNO FOREIGN KEY (DEPTNO) REFERENCES DEPT (DEPTNO);