Table Creation With Constraints in Oracle :EMP Table

FOR SYBCA , MCA , Msc IT Students

TABLE NAME : EMP

create table emp
(
empno number(4) primary key,
ename varchar2(10),
job varchar2(9),
mg number(4),
hiredate date,
sal number(7,2),
comm number(7,2),
deptno number(2) references dept(deptno)
);

insert into emp values(7369,'smith','clerk',7902,'17-dec-80',800,0,20);
insert into emp values(7499,'allen','salesman',7698,'20-feb-81',1600,300,30);
insert into emp values(7521,'ward','salesman',7698,'22-feb-81',1250,500,30);
insert into emp values(7566,'jones','manager',7839,'02-apr-81',2975,0,20);
insert into emp values(7654,'martin','salesman',7698,'28-sep-81',1250,0,30);
insert into emp values(7698,'blake','manager',7839,'01-may-81',2850,0,30);
insert into emp values(7782,'clark','manager',7839,'09-jun-81',2450,0,10);
insert into emp values(7788,'scott','analyst',7566,'09-dec-81',3000,0,20);
insert into emp values(7839,'king','president',,'17-nov-81',5000,0,10);
insert into emp values(7844,'turner','salemsman',7698,'08-sep-81',1500,0,30);
insert into emp values(7876,'adams','clerk',7788,'12-jan-83',1100,0,20);
insert into emp values(7900,'james','clerk',7698,'03-dec-81',950,0,30);
insert into emp values(7902,'ford','analyst',7566,'03-dec-81',3000,0,20);
insert into emp values(7934,'miller','clerk',7782,'23-jan-82',1300,0,10);