My First Project:
A Used Car Sales System for SPM

Every developer has a first project that sparked everything. Mine was a Used Car Sales Management System that I built during secondary school, around the time I was preparing for SPM.

Looking back at it now, as a final-year Computer Science student, is both a little embarrassing and very motivating. This post is about what I built, what I learned, and what I would change if I built it again today.

01 Where It All Started

I wanted to build something real, not just follow tutorials. A used car dealer needs to keep track of vehicles for sale and the customers interested in them, which felt like a practical problem I could solve with a simple web system.

I had very little experience at the time. Most of the project was learning as I went: how a web page talks to a server, how data is stored in a database, and why things break when one small detail is wrong.

02 What I Built

The system let a user manage vehicle listings and customer information through a web interface:

In other words, it was a classic CRUD application: Create, Read, Update and Delete. Simple, but it covered the core of almost every data-driven system I have built since.

03 What It Taught Me

• How the web works: forms send data to PHP, PHP talks to MySQL, and the result is turned back into a page.
• Relational databases: designing tables, choosing keys and writing SQL queries.
• Debugging: reading error messages carefully and testing one change at a time.
• Persistence: finishing a project, even when it is not perfect, teaches more than starting many.

04 What I Would Do Differently Today

With what I know now, there are several things I would change if I rebuilt the system:

• Security first: use prepared statements to prevent SQL injection and hash passwords properly.
• Plan before coding: draw an ERD and gather requirements before touching the code, as I learned in Software Engineering.
• Separate concerns: keep database logic, business logic and HTML apart instead of mixing them in one file.
• Use version control: track changes with Git and GitHub so mistakes are easy to undo.
• Responsive design: use a framework like Bootstrap so the system works on phones too.
• Test properly: write test cases for each feature instead of only clicking around.

Here is a small example of how I would write a query today, compared with how I probably wrote it back then:

// Then: user input placed directly into the SQL (unsafe)
$sql = "SELECT * FROM cars WHERE model = '" . $_GET['model'] . "'";

// Now: a prepared statement keeps data and SQL separate
$stmt = $conn->prepare('SELECT * FROM cars WHERE model = ?');
$stmt->bind_param('s', $_GET['model']);
$stmt->execute();
$result = $stmt->get_result();

05 From SPM to Final Year