02 Project Setup

Goal

Verify the pdo_sqlite extension is available and create a project directory. After this page you have a folder every later page adds a file to — no package manager step needed.

Prerequisites

• Install PHP
• Why Persistence

Verify pdo_sqlite Is Enabled

Unlike Go's modernc.org/sqlite (a third-party module fetched with go get), PHP's SQLite driver is a built-in extension — no package manager step required, consistent with the "batteries included" pitch from the Introduction.

php -m | grep pdo_sqlite

Expected output:

pdo_sqlite

If it's missing, your PHP build was compiled without it — reinstall via your platform's package manager (e.g. brew reinstall php on macOS bundles it by default).

Create the Project Directory

mkdir items && cd items

Every file this tier adds goes here: db.php (page 03), store.php (page 04), handlers.php (pages 05-06), and the final router.php (page 07, extending the router script from 08 Hello HTTP).

Multiple Files: require_once

The beginner tier never split code across files. This tier does, so it's worth introducing require's family now: it pulls in another PHP file's code at the point it's called, similar to what import/go get do in other languages — except there's no module system underneath it, just "run this other file's top-level code here."

<?php
require_once __DIR__ . '/db.php';

__DIR__ is a magic constant holding the current file's directory — using it instead of a relative path keeps require_once working regardless of what directory you run php from.

Use require_once, not require, for anything declaring functions or classes. Plain require re-runs the file every time it's called — harmless for a file of pure logic, but a fatal error ("cannot redeclare function/class") the moment two different entry points both require the same file in one process. This tier hits that exact case on page 08: both test files need db.php, and PHPUnit loads them together in a single run. require_once tracks which files it's already pulled in and skips the second load — the fix, and the default you should reach for.

Checkpoint

php -m | grep pdo_sqlite

Should print pdo_sqlite with no errors. No file to check yet — this page is setup only.

Next

Continue to 03 Schema.