jz042

/* Delete the tables if they already exist */
drop table if exists Movie;
drop table if exists Reviewer;
drop table if exists Rating;

/* Create the schema for our tables */
create table Movie(mID int, title text, year int, director text);
create table Reviewer(rID int, name text);
create table Rating(rID int, mID int, stars int, ratingDate date);

jz042

-- SQL Movie-Rating View Modification Exercises[
-- Question 1
-- Write an instead-of trigger that enables updates to the title attribute of view LateRating.
-- Policy: Updates to attribute title in LateRating should update Movie.title for the corresponding movie. (You may assume attribute mID is a key for table Movie.) Make sure the mID attribute of view LateRating has not also been updated -- if it has been updated, don't make any changes. Don't worry about updates to stars or ratingDate.
-- 
-- Question 2
-- Write an instead-of trigger that enables updates to the stars attribute of view LateRating.
-- Policy: Updates to attribute stars in LateRating should update Rating.stars for the corresponding movie rating. (You may assume attributes [mID,ratingDate] together are a key for table Rating.) Make sure the mID and ratingDate attributes of view LateRating have not also been updated -- if either one has been updated, don't make any changes. Don't worry about updates to title.
-- 
-- Question 3

jz042

/* Delete the tables if they already exist */
drop table if exists Highschooler;
drop table if exists Friend;
drop table if exists Likes;
 
/* Create the schema for our tables */
create table Highschooler(ID int, name text, grade int);
create table Friend(ID1 int, ID2 int);
create table Likes(ID1 int, ID2 int);