create table dept(
  deptno number(2,0),
  dname  varchar2(14),
  loc    varchar2(13),
  constraint pk_dept primary key (deptno)
);
 
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),
  constraint pk_emp primary key (empno),
  constraint fk_deptno foreign key (deptno) references dept (deptno)
);
 

create table bonus(
  ename varchar2(10),
  job   varchar2(9),
  sal   number,
  comm  number
);
 
create table salgrade(
  grade number,
  losal number,
  hisal number
);