Lecture 1: Introduction to Databases

Duration: 2 hours | Theory: 30 min | Practice: 90 min

What This Lecture Covers

Slides 1-5 introduce why databases beat files for data storage. Students see the "big picture" roadmap, then you jump into DDL/DML concepts (slides 6-10). The real work starts around slide 11 where they create their first tables.

Skip the iframe on slide 2 - it's a draw.io diagram that doesn't work well in presentation mode. Just explain verbally: "databases centralize data, files scatter it everywhere."

Before Class Starts

Send students a checklist 24 hours before:

• Download MySQL ZIP (not installer) from mysql.com
• Extract to C:\mysql or ~/mysql
• Don't run anything yet - we'll do it together

This saves 30 minutes of "wait while it downloads" during class. If students didn't prepare, have them pair with someone who did.

Slide-by-Slide Walkthrough

Slides 1-7: Why Databases? (15 min)

After the title slide, show slide 3 (databases vs files diagram). Ask students: "Who's used Excel for data? What broke when the file got big?" Use their answers to intro the three database languages on slides 6-7.

Don't spend more than 2 minutes per slide here. The goal is to get them curious, not to memorize DDL/DML/DCL definitions.

Slides 8-12: Table Structure (10 min)

Slide 8 introduces tables, rows, columns. Draw this on a whiteboard alongside the slide - students understand better with a hand-drawn table than the formal SVG diagrams.

Slides 11-12 cover constraints and keys. Keep it brief: "PRIMARY KEY = unique ID, FOREIGN KEY = link to another table." You'll reinforce this later when they build actual tables.

Live Demo: First Database (20 min)

Now close the slides and open MySQL. Walk through creating a database step by step:

CREATE DATABASE lecture1_demo;
USE lecture1_demo;

CREATE TABLE customers (
    customer_id INT PRIMARY KEY AUTO_INCREMENT,
    first_name VARCHAR(50) NOT NULL,
    last_name VARCHAR(50) NOT NULL,
    email VARCHAR(100) UNIQUE
);

INSERT INTO customers (first_name, last_name, email)
VALUES ('Alice', 'Johnson', 'alice@test.com');

SELECT * FROM customers;

-- Deliberately try to break it
INSERT INTO customers (first_name, last_name, email)
VALUES ('Bob', 'Smith', 'alice@test.com');
-- Error! Duplicate email - this is GOOD, show them the error

Explain each line as you type it. When the duplicate email fails, celebrate it: "See? The database stopped me from adding bad data. Files can't do that."

Student Exercise 1: Library System (40 min)

Give students this challenge (no slide for this, just verbally):

Build a library database with:

• books table: book_id (PK, auto-increment), title, author, isbn (unique), published_year, available_copies (can't be negative)
• members table: member_id (PK), first_name, last_name, email (unique), join_date (defaults to today)

Then insert 3 books and 3 members, and write queries to find books published after 2020.

Walk around while they work. Common mistakes:

• Forgetting USE database_name; before CREATE TABLE
• Missing semicolons
• Using INT for email or VARCHAR for numbers
• Quotes around numbers: INSERT INTO books VALUES ('1', 'Title') instead of (1, 'Title')

Student Exercise 2: Breaking Things (30 min)

This exercise teaches constraints by letting students hit errors:

1. Try to insert a book with duplicate ISBN - what happens?
2. Try to insert a member with an existing email - what error?
3. Try to insert a book with -5 available_copies (if you added CHECK constraint)
4. Create two books with the same book_id manually (without AUTO_INCREMENT) - does it work?

After they've tried, discuss: "These errors aren't bugs - they're features. The database is protecting your data."

Slides 25+: MySQL Setup (Final 20 min)

Now jump to the MySQL installation slides at the end. Walk through together:

Slide 26: Initialize MySQL

cd C:\mysql\bin
mysqld --initialize-insecure --console

Slide 27: Start the server (keep this terminal open!)

mysqld --console

Slide 28: Connect (new terminal)

mysql -u root
SHOW DATABASES;

Students who finish early: install DBeaver (slides 29-33). But command line is sufficient for now.

Common Issues & Fixes

"I get 'command not found' when running mysql"

They're not in the bin directory. Have them cd C:\mysql\bin first (Windows) or add MySQL to PATH.

"Error: Can't connect to MySQL server"

The mysqld server isn't running. Check if they have the server terminal open with mysqld --console.

"Table already exists" error

They ran CREATE TABLE twice. Show them: DROP TABLE table_name; then try again.

Homework

Personal movie collection database with at least 5 movies. Must include: title, director, year, genre, rating (0-10), watched (yes/no). Write queries to find unwatched movies and movies rated above 7.

Next lecture preview: "We'll learn to design databases properly before coding. You'll draw ER diagrams for complex systems like e-commerce sites."