1.
create table scott.post
( post1 char(3) ,
  post2 char(3) ,
  addr	varchar2(60) not null,
  CONSTRAINT post_pk PRIMARY KEY(post1,post2)
); 

create table scott.member
(
	id 	number(4) 	primary key,
	name 	varchar(10)	not null,
	sex	char(1)		check(sex = 1 or sex =0),
	jumin1	char(6),
	jumin2 	char(7),
	tel	varchar(7),
	post1	char(3),
	post2	char(3),
	addr	varchar(60),
	constraint member_jumin_uk unique(jumin1,jumin2),
	constraint member_post_fk foreign key (post1,post2) references scott.post(post1,post2)
);

2.
create table emp_demo
as select empno, ename, job, mgr, deptno
     from emp;

3.
create table emp_dept
as
select e.empno, e.ename, e.job, d.dname, d.loc 
from emp e, dept d
where e.deptno = d.deptno;

4.
create table emp_grade
as
select e.empno, e.ename, e.job, e.sal, e.comm, s.grade
from emp e, salgrade s
where e.sal between s.losal and s.hisal;

5.
alter table scott.dept
disable primary key;

6.
alter table emp_grade
add constraint emp_grade_empno_pk primary key(empno);

7.
alter table emp_grade
modify sal number(12,4);

8.
drop table scott.emp_dept;
drop table scott.emp_grade;

9.
alter table bonus
add etc varchar2(50);

10.
alter table emp
drop column comm;

11.
alter table emp
add constraint emp_ename_uni unique(ename);

12.
select a.table_name,b.column_name,a.constraint_name,a.constraint_type,a.search_condition,a.status
from user_constraints a,user_cons_columns b
where a.constraint_name=b.constraint_name and a.table_name='EMP';

13.
create table scott.my_data
( 
	id 	number(4)	primary key,
	name	varchar2(10),
	userid	varchar2(30),
	salary	number(10,2)
); 

14.
insert into scott.my_data(id, name, userid, salary)
values(1,'Scoot', 'sscott', 10000);

insert into scott.my_data(id, name, userid, salary)
values(2,'Ford', 'fford', 13000);

insert into scott.my_data(id, name, userid, salary)
values(3,'Patel', 'ppatel', 33000);

insert into scott.my_data(id, name, userid, salary)
values(4,'Report', 'rreport', 23500);

insert into scott.my_data(id, name, userid, salary)
values(5,'Good', 'ggood', 44450);

15.
update emp
set sal = 3000
where sal > 3000;

16.
update emp
set job = (select job from emp where ename='SMITH')
where deptno = (select deptno from emp where ename ='SCOTT');

17.
update emp
set (job, sal) = (select job, sal from emp where ename ='ALLEN')
where ename= 'SCOTT';

18.
update emp
set deptno = 91
where deptno = 10;

19.
update dept
set deptno = 15
where deptno = 10;

20.
delete from emp
where empno = 7499;

21.
delete from emp
where to_char(hiredate,'yy') = 83;

22.
delete from emp
where deptno = (select deptno from dept where dname = 'SALES');

23.
delete from dept
where dname = 'ACCOUNTING';