create table departments(
	did char(5) primary key,
	dname varchar2(25) not null,
	location varchar2(15));


create table students( 
sid char(4) primary key,
name varchar2(25) not null,
gpa number(3,4) check  (gpa>=0 and gpa<=4),
major char(5) ,
foreign key(major) references departments(did));

create table courses(
	cid char(5) primary key,
	title varchar2(15),
	department char(5),
credits number,
	foreign key (department) references departments(did));

create table takes(
	sid char(4),
	cid char(5),
	grade char(1) check (grade in (‘A’,’B’,’C’,’F’)),
	primary key(sid,cid),
	foreign key (sid) references students (sid),
	foreign key (cid) references courses (cid));



insert into departments values (‘csci’, ’computer science’, ‘molinaro’);
insert into students values (‘1234’,’Joe’,2,’csci’);

update students
set gpa=gpa+1
where sid=’1234’;

delete
from students
where gpa<4;