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README.md

@@ -28,7 +28,7 @@ Before this starting this lab, you should have learnt about:
 
 - Fundamental concepts of database design, including entities, attributes, primary keys, and foreign keys.
 - Basic comprehension of SQL syntax and statements, such as CREATE, INSERT INTO, UPDATE, and DELETE.
-- Familiarity with the concept of NOT NULL constraints and data types in SQL.
+- Familiarity with the concept of NOT NULL constraints and data types in SQL
 
   <br>
   <hr> 

create.sql

@@ -0,0 +1,61 @@
+-- create.sql
+CREATE DATABASE IF NOT EXISTS lab_mysql;
+USE lab_mysql;
+
+-- Drop in FK-safe order
+DROP TABLE IF EXISTS invoices;
+DROP TABLE IF EXISTS salespersons;
+DROP TABLE IF EXISTS customers;
+DROP TABLE IF EXISTS cars;
+
+-- Cars
+CREATE TABLE cars (
+  id           INT AUTO_INCREMENT PRIMARY KEY,
+  vin          VARCHAR(17) NOT NULL,
+  manufacturer VARCHAR(50) NOT NULL,
+  model        VARCHAR(100) NOT NULL,
+  model_year   YEAR NOT NULL,
+  color        VARCHAR(30) NOT NULL
+  -- Optionally enforce VIN uniqueness after cleaning:
+  -- , UNIQUE KEY uk_cars_vin (vin)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+-- Customers
+CREATE TABLE customers (
+  id            INT AUTO_INCREMENT PRIMARY KEY,
+  cust_id       INT NOT NULL,                -- business ID (not PK)
+  cust_name     VARCHAR(100) NOT NULL,
+  cust_phone    VARCHAR(30),
+  cust_email    VARCHAR(100),
+  cust_address  VARCHAR(150),
+  cust_city     VARCHAR(100),
+  cust_state    VARCHAR(100),
+  cust_country  VARCHAR(100),
+  cust_zipcode  VARCHAR(20),
+  UNIQUE KEY uk_customers_cust_id (cust_id)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+-- Salespersons
+CREATE TABLE salespersons (
+  id       INT AUTO_INCREMENT PRIMARY KEY,
+  staff_id INT NOT NULL,                     -- business ID (not PK)
+  name     VARCHAR(100) NOT NULL,
+  store    VARCHAR(100) NOT NULL,
+  UNIQUE KEY uk_salespersons_staff_id (staff_id)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+-- Invoices (car sale)
+CREATE TABLE invoices (
+  id             INT AUTO_INCREMENT PRIMARY KEY,
+  invoice_number BIGINT NOT NULL,
+  invoice_date   DATE NOT NULL,
+  car_id         INT NOT NULL,
+  customer_id    INT NOT NULL,
+  salesperson_id INT NOT NULL,
+  UNIQUE KEY uk_invoice_number (invoice_number),
+  -- Enforce 1 sale per car (optional but recommended):
+  UNIQUE KEY uk_invoices_car_once (car_id),
+  CONSTRAINT fk_inv_car         FOREIGN KEY (car_id)         REFERENCES cars(id)         ON DELETE RESTRICT,
+  CONSTRAINT fk_inv_customer    FOREIGN KEY (customer_id)    REFERENCES customers(id)    ON DELETE RESTRICT,
+  CONSTRAINT fk_inv_salesperson FOREIGN KEY (salesperson_id) REFERENCES salespersons(id) ON DELETE RESTRICT
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

delete.sql

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+-- delete.sql (variant A)
+USE lab_mysql;
+DELETE FROM cars WHERE id = 4;
+
+-- Verify it’s gone
+SELECT id, vin, manufacturer, model FROM cars ORDER BY id;
+
+-- delete.sql (variant B)
+USE lab_mysql;
+
+-- Remove duplicate VIN rows, keeping the smallest id for each VIN
+DELETE c1 FROM cars c1
+JOIN cars c2
+  ON c1.vin = c2.vin
+ AND c1.id  > c2.id;
+
+-- After cleaning, prevent future duplicates (add UNIQUE index)
+ALTER TABLE cars ADD UNIQUE KEY uk_cars_vin (vin);
+
+-- Verify
+SELECT vin, COUNT(*) AS n FROM cars GROUP BY vin HAVING n > 1;

seeding.sql

@@ -0,0 +1,34 @@
+-- seeding.sql
+USE lab_mysql;
+
+-- Cars (note duplicated VIN for ids 5 and 6 on purpose for Bonus)
+INSERT INTO cars (id, vin, manufacturer, model, model_year, color) VALUES
+(1, '3K096I98581DHSNUP', 'Volkswagen', 'Tiguan', 2019, 'Blue'),
+(2, 'ZM8G7BEUQZ97IH46V', 'Peugeot', 'Rifter', 2019, 'Red'),
+(3, 'RKXVNNIHLVVZOUB4M', 'Ford', 'Fusion', 2018, 'White'),
+(4, 'HKNDGS7CU31E9Z7JW', 'Toyota', 'RAV4', 2018, 'Silver'),
+(5, 'DAM41UDN3CHU2WVF6', 'Volvo', 'V60', 2019, 'Gray'),
+(6, 'DAM41UDN3CHU2WVF6', 'Volvo', 'V60 Cross Country', 2019, 'Gray');
+
+-- Customers (1-based IDs to match invoices)
+INSERT INTO customers (id, cust_id, cust_name, cust_phone, cust_email, cust_address, cust_city, cust_state, cust_country, cust_zipcode) VALUES
+(1, 10001, 'Pablo Picasso', '+34 636 17 63 82', NULL, 'Paseo de la Chopera, 14', 'Madrid', 'Madrid', 'Spain', '28045'),
+(2, 20001, 'Abraham Lincoln', '+1 305 907 7086', NULL, '120 SW 8th St', 'Miami', 'Florida', 'United States', '33130'),
+(3, 30001, 'Napoléon Bonaparte', '+33 1 79 75 40 00', NULL, '40 Rue du Colisée', 'Paris', 'Île-de-France', 'France', '75008');
+
+-- Salespersons
+INSERT INTO salespersons (id, staff_id, name, store) VALUES
+(1, 1, 'Petey Cruiser', 'Madrid'),
+(2, 2, 'Anna Sthesia', 'Barcelona'),
+(3, 3, 'Paul Molive', 'Berlin'),
+(4, 4, 'Gail Forcewind', 'Paris'),
+(5, 5, 'Paige Turner', 'Miami'),
+(6, 6, 'Bob Frapples', 'Mexico City'),
+(7, 7, 'Walter Melon', 'Amsterdam'),
+(8, 8, 'Shonda Leer', 'São Paulo');
+
+-- Invoices
+INSERT INTO invoices (id, invoice_number, invoice_date, car_id, customer_id, salesperson_id) VALUES
+(1, 852399038, '2018-08-22', 1, 1, 3),
+(2, 731166526, '2018-12-31', 3, 3, 5),
+(3, 271135104, '2019-01-22', 2, 2, 7);

update.sql

@@ -0,0 +1,20 @@
+-- update.sql
+USE lab_mysql;
+
+-- If Workbench complains about safe updates:
+SET SQL_SAFE_UPDATES = 0;
+
+UPDATE customers SET cust_email = '[email protected]'
+WHERE cust_name = 'Pablo Picasso';
+
+UPDATE customers SET cust_email = '[email protected]'
+WHERE cust_name = 'Abraham Lincoln';
+
+UPDATE customers SET cust_email = '[email protected]'
+WHERE cust_name = 'Napoléon Bonaparte';
+
+-- Optional: turn safe updates back on
+SET SQL_SAFE_UPDATES = 1;
+
+-- Verify
+SELECT id, cust_name, cust_email FROM customers ORDER BY id;