Merge branch 'master' of gitlab.doc.gold.ac.uk:data-networks-web/lab-exercises

README.md

@@ -27,7 +27,6 @@ Here's a reminder of the topics covered in each lab session. Please note, topics
 
 ### Lab 4: Security and integrity! (27/28 Oct)
 - Data normalisation
-- Transactions (SQL) 
 - Backup/restore
 
 ### Lab 5: Using PHP to interact with a MySQL database (10/11 Nov)
@@ -45,7 +44,7 @@ Here's a reminder of the topics covered in each lab session. Please note, topics
 - Basic data sanitization methods
 
 ### Lab 8: Implementing transactions in PHP (1/2 Dec)
-- Examples
+- Transaction examples
 
 ### Lab 9: Introduction to MongoDB (non-assessed) (8/9 Dec)
 - Document structure

lab-2/music-store-app/sql/schema.sql

@@ -10,8 +10,9 @@ CREATE TABLE Genre (
 );
 
 /* Define table for storing act (i.e. a group or solo artist)
-ON DELETE CASCADE not needed in this
-case as a Band does not HAVE to have an associated genre */
+ON DELETE CASCADE not used in this case as we don't want bands 
+being deleted if their genre is deleted. We'd rather an error
+was raised. */
 CREATE TABLE Band (
 	id INT AUTO_INCREMENT,
 	name VARCHAR(50) NOT NULL,

lab-3/music-store-app/sql/dummy_data.sql

+INSERT INTO Genre (name)
+VALUES
+('Reggae'),
+('Funk and Soul'),
+('Jazz'),
+('Classical'),
+('Electronic'),
+('Pop');
+
+INSERT INTO Band (name, genre_id)
+VALUES
+('The Wailers', 1),
+('The Aces', 2),
+('The Beatles', 6);
+
+INSERT INTO Artist (first_name, last_name, band_id) 
+VALUES
+('Bob', 'Marley', 1),
+('Peter', 'Tosh', 1),
+('Burning', 'Spear', NULL),
+('Alton', 'Ellis', NULL),
+('Gregory', 'Issacs', NULL),
+('Desmond', 'Dekker', 2),
+('John', 'Lennon', 3),
+('Madonna', NULL, NULL);
+
+INSERT INTO Album (upc, title, year, artist_id, price, genre_id) 
+VALUES
+('123425364732', 'Soul Rebel', 1970, 1, 25.99, 1 ),
+('017263547261', 'Catch A Fire', 1973, 1, 25.99, 1 ),
+('018263526272', 'Natty Dread', 1974, 1, 20.99, 1 ),
+('018273527273', 'Babylon By Bus', 1978, 1, 24.99, 1 ),
+('491827364626', 'Night Nurse', 1982, 5, 17.99, 1 ),
+('018276272828', 'Mr Issacs', 1982, 5, 9.99, 1 ),
+('018273662728', 'Black and Dekker', 1980, 6, 19.99, 1 ),
+('726517237627', 'Sunday Coming', 1970, 4, 15.99, 1 ),
+('018274372722', 'Imagine', 1971, 7, 11.99, 6 ),
+('018273727287', 'Like a Virgin', 1984, 8, 9.99, 6 );
+
+INSERT INTO Track (name, album_upc, track_number)
+VALUES
+('Sunday Coming', '726517237627', 1),
+('Imagine', '018274372722', 1),
+('Material Girl', '018273727287', 1),
+('Angel', '018273727287', 2),
+('Like a Virgin', '018273727287', 3),
+('Crippled Inside', '018274372722', 2),
+('These Eyes', '726517237627', 2),
+('Hurting Me', '726517237627', 3);
+
+INSERT INTO Customer (username, email_address, password, first_name, last_name, address_1, address_2, postcode)
+VALUES
+('sharr003', 's.harriet@gold.ac.uk', 'SOME_HASHED_VALUE', 'Sorrel', 'Harriet', '12 Fake Street', 'London', 'SE140PL');
+
+INSERT INTO Transaction (customer_id, delivery)
+VALUES
+(1, 'next working day');
+
+INSERT INTO LineItem (trans_id, album_upc, quantity)
+VALUES
+(1, '018273727287', 1),
+(1, '018274372722', 2);

lab-3/music-store-app/sql/practice_queries.sql

+/* Minimum functional requirements of
+Music Store App and their associated queries.
+Where variations are given they are
+given in order of increasing complexity */
+
+/* 1a. Retrieve a list of Albums
+Include the UPC, title, price, artist name
+and genre in the result-set.
+Order by title (a-z) */
+SELECT Album.title, Album.price, Artist.first_name, Artist.last_name, Genre.name AS genre 
+FROM Album /* notice the use of a column alias! */
+INNER JOIN Artist
+	ON Album.artist_id=Artist.id
+INNER JOIN Genre
+	ON Album.genre_id=Genre.id
+ORDER BY title ASC; /* causes results to be ordered by album title */
+
+/* 1b. Retrieve a list of Albums
+Include the UPC, title, price, artist name,
+genre, and number of tracks in the result-set.
+Include only albums which have tracks in DB.
+Order by title (a-z) */
+SELECT Album.title, Album.price, Artist.first_name, Artist.last_name, Genre.name AS genre, (SELECT COUNT(*) FROM Track WHERE Album.upc=Track.album_upc) AS num_tracks 
+FROM Album /* notice the nested query, aggregate function and aliases! */
+INNER JOIN Track
+	ON Album.upc=Track.album_upc 
+INNER JOIN Artist 
+	ON Album.artist_id=Artist.id 
+INNER JOIN Genre
+	ON Album.genre_id=Genre.id 
+ORDER BY title ASC;
+
+/* 1c. Retrieve a list of Albums
+Include the UPC, title, price, artist name,
+genre, and number of tracks in the result-set.
+Include ALL albums, even those without tracks.
+Order by title (a-z) */
+SELECT Album.title, Album.price, Artist.first_name, Artist.last_name, Genre.name AS genre, (SELECT COUNT(*) FROM Track WHERE Album.upc=Track.album_upc) AS num_tracks
+FROM Album /* notice the nested query, aggregate function and aliases! */
+LEFT JOIN Track /* LEFT JOIN causes all Albums to be returned, even when no matching record in Track table */
+	ON Album.upc=Track.album_upc 
+INNER JOIN Artist 
+	ON Album.artist_id=Artist.id 
+INNER JOIN Genre
+	ON Album.genre_id=Genre.id 
+ORDER BY title ASC;
+
+/* ------------------------------------ */
+
+/* 2. Retrieve a list of tracks
+associated with a specific album */
+SELECT t.name AS track, t.track_number, a.title AS album /* notice use of column aliases! */
+FROM Track t /* notice use of table aliases! */
+INNER JOIN Album a
+	ON t.album_upc=a.upc
+WHERE a.upc='018274372722' /* EXAMPLE */
+ORDER BY track_number ASC;
+
+/* ------------------------------------ */
+
+/* 3. Insert a new track */
+INSERT INTO Track (name, album_upc, track_number)
+VALUES
+('Sunday Coming', '726517237627', 1); /* EXAMPLE */
+
+/* ------------------------------------ */
+
+/* 4. Delete a track */
+DELETE FROM Track WHERE album_upc='726517237627'; /* EXAMPLE */

lab-3/music-store-app/sql/schema.sql

+/* Delete existing tables in reverse order of creation
+so as not to violate any foreign key constraints */
+DROP TABLE IF EXISTS LineItem, Transaction, Customer, Track, Album, Artist, Band, Genre;
+
+/* Define table for genres */
+CREATE TABLE Genre (
+	id INT AUTO_INCREMENT,
+	name VARCHAR(25) UNIQUE NOT NULL,
+	PRIMARY KEY (id)
+);
+
+/* Define table for storing act (i.e. a group or solo artist)
+ON DELETE CASCADE not used in this case as we don't want bands 
+being deleted if their genre is deleted. We'd rather an error
+was raised. */
+CREATE TABLE Band (
+	id INT AUTO_INCREMENT,
+	name VARCHAR(50) NOT NULL,
+	genre_id INT,
+	PRIMARY KEY (id),
+	FOREIGN KEY (genre_id)
+		REFERENCES Genre (id)
+);
+
+/* Define table for storing artists */
+CREATE TABLE Artist (
+	id INT AUTO_INCREMENT,
+	first_name VARCHAR(25) NOT NULL,
+	last_name VARCHAR(25),
+	band_id INT,
+	PRIMARY KEY (id),
+	FOREIGN KEY (band_id)
+		REFERENCES Band (id) 
+);
+
+/* Define table for storing albums */
+CREATE TABLE Album (
+	upc CHAR(12),
+	title VARCHAR(50) NOT NULL,
+	year YEAR(4),
+	artist_id INT,
+	compilation BOOLEAN NOT NULL DEFAULT 0,
+	price DECIMAL(5, 2) unsigned NOT NULL,
+	genre_id INT,
+	PRIMARY KEY (upc),
+	FOREIGN KEY (artist_id)
+		REFERENCES Artist (id), 
+	FOREIGN KEY (genre_id)
+		REFERENCES Genre (id)
+);
+
+
+/* Define table for storing single tracks 
+ON DELETE CASCADE will ensure no track
+is left that isn't linked to an album.
+ON UPDATE CASCADE will inherit any changes 
+to the Album UPC (Universal Product Code).
+A composite PRIMARY KEY is used here to
+ensure the track_number is unique
+on any given album */
+CREATE TABLE Track (
+	name VARCHAR(50) NOT NULL,
+	album_upc CHAR(12) NOT NULL,
+	track_number INT,
+	PRIMARY KEY (album_upc, track_number),
+	FOREIGN KEY (album_upc)
+		REFERENCES Album (upc)
+		ON UPDATE CASCADE
+		ON DELETE CASCADE
+);
+
+/* Define table for storing customers */
+CREATE TABLE Customer (
+	id INT AUTO_INCREMENT,
+	username VARCHAR(25) UNIQUE NOT NULL,
+	email_address VARCHAR(50) UNIQUE NOT NULL,
+	password VARCHAR(64),
+	first_name VARCHAR(50) NOT NULL,
+	last_name VARCHAR(50) NOT NULL,
+	address_1 VARCHAR(50) NOT NULL,
+	address_2 VARCHAR(50),
+	postcode VARCHAR(10) NOT NULL,
+	PRIMARY KEY (id)
+);
+
+/* Define table for storing orders */
+CREATE TABLE Transaction (
+	id INT AUTO_INCREMENT,
+	customer_id INT NOT NULL,
+	delivery ENUM('first class','second class','next working day'),
+	PRIMARY KEY (id),
+	FOREIGN KEY (customer_id)
+		REFERENCES Customer(id)
+		ON DELETE CASCADE
+);
+
+/* Define table for storing line items */
+CREATE TABLE LineItem (
+	id INT AUTO_INCREMENT,
+	trans_id INT NOT NULL,
+	album_upc CHAR(12) NOT NULL,
+	quantity INT NOT NULL DEFAULT 1,
+	PRIMARY KEY (id),
+	FOREIGN KEY (trans_id)
+		REFERENCES Transaction (id)
+		ON DELETE CASCADE,
+	FOREIGN KEY (album_upc)
+		REFERENCES Album (upc)
+		ON DELETE CASCADE
+);