REM referential integrity problem

insert into enrollments
values ('66419', '9876', '','A');

REM fixed

insert into enrollments
values ('66419', '1011', '','A');

REM alternate form

insert into enrollments (studentid, sectionid, grade)
values ('7070',66419,'A');

REM not supported by Oracle

insert into enrollments (studentid, sectionid, grade)
values (7171,66419,'B'),
(5555,66419,'C');

REM entity integrity problem

insert into students (studentid, first, last, year)
values (1093,'James','Johnson','Fr');

REM insert based on query

insert into dept_info (dname,num_classes,max_enroll)
select dept, count(*), max(stoppoint) 
from sections
group by dept;

REM  delete 1 row

DELETE 
from students 
where studentid = '1234';

REM delete multiple rows

DELETE from students
where gpa < 2.5;

REM trying to delete joined info

DELETE from students, enrollments
WHERE studentid = '1011';

REM delete when reference exists

DELETE from students
WHERE studentid = '1011';

REM oops deleted them all

delete from students;

REM make change "permanent"

commit;

REM back off to last commit

rollback;

UPDATE students
SET hometown = 'Vorhees'
WHERE studentid = '1113';

UPDATE students
SET hometown = 'Los Angeles', balancedue = '1000'
WHERE studentid = '1212';

UPDATE students
SET balancedue = balancedue + 500
WHERE studentid = '1212';

UPDATE students
SET year = 'Jr'
WHERE studentid = '2121';

UPDATE students
SET year = 'Sr'
WHERE numcreditsearned >= 90;