Deleting Records with PDO

Use a bound primary key to remove exactly the intended record.

The examples focus on the operation itself, including the important distinction: SELECT reads rows; DELETE is a write operation.

What It Does

Use the examples below to observe the behavior on a small dataset before extending it to application code.

Before You Start

The examples use PHP 8.2+ features where shown. Database snippets require the corresponding PDO driver, demo tables, and credentials configured outside source code.

Example 1: Basic Use

The delete runs in a transaction; this example treats zero deleted rows as an application error.

<?php
$pdo = new PDO(
    "mysql:host=" . (getenv("DB_HOST") ?: "127.0.0.1") . ";dbname=" . (getenv("DB_NAME") ?: "demo") . ";charset=utf8mb4",
    getenv("DB_USER") ?: "app",
    getenv("DB_PASSWORD") ?: "",
    [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, PDO::ATTR_EMULATE_PREPARES => false]
);
$id = 6;
$pdo->beginTransaction();
try {
$stmt = $pdo->prepare("DELETE FROM users WHERE id = ?");
$stmt->execute([$id]);
if ($stmt->rowCount() !== 1) { throw new RuntimeException("No matching user"); }
$pdo->commit();
} catch (Throwable $e) { if ($pdo->inTransaction()) { $pdo->rollBack(); } throw $e; }

This example is meant for a configured application environment; output depends on the installed extension, external service, or database contents.

Example 2: Checking Behavior

The delete runs in a transaction; this example treats zero deleted rows as an application error.

<?php
$pdo = new PDO(
    "mysql:host=" . (getenv("DB_HOST") ?: "127.0.0.1") . ";dbname=" . (getenv("DB_NAME") ?: "demo") . ";charset=utf8mb4",
    getenv("DB_USER") ?: "app",
    getenv("DB_PASSWORD") ?: "",
    [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, PDO::ATTR_EMULATE_PREPARES => false]
);
$id = 9;
$pdo->beginTransaction();
try {
$stmt = $pdo->prepare("DELETE FROM users WHERE id = ?");
$stmt->execute([$id]);
if ($stmt->rowCount() !== 1) { throw new RuntimeException("No matching user"); }
$pdo->commit();
} catch (Throwable $e) { if ($pdo->inTransaction()) { $pdo->rollBack(); } throw $e; }

This example is meant for a configured application environment; output depends on the installed extension, external service, or database contents.

Example 3: Practical Example

The delete runs in a transaction; this example treats zero deleted rows as an application error.

<?php
$pdo = new PDO(
    "mysql:host=" . (getenv("DB_HOST") ?: "127.0.0.1") . ";dbname=" . (getenv("DB_NAME") ?: "demo") . ";charset=utf8mb4",
    getenv("DB_USER") ?: "app",
    getenv("DB_PASSWORD") ?: "",
    [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, PDO::ATTR_EMULATE_PREPARES => false]
);
$id = 17;
$pdo->beginTransaction();
try {
$stmt = $pdo->prepare("DELETE FROM users WHERE id = ?");
$stmt->execute([$id]);
if ($stmt->rowCount() !== 1) { throw new RuntimeException("No matching user"); }
$pdo->commit();
} catch (Throwable $e) { if ($pdo->inTransaction()) { $pdo->rollBack(); } throw $e; }

This example is meant for a configured application environment; output depends on the installed extension, external service, or database contents.

Important Behavior and Edge Cases

rowCount reports affected rows, not guaranteed existence before deletion; never construct identifiers from request strings.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Use a bound primary key to remove exactly the intended record.
• rowCount reports affected rows, not guaranteed existence before deletion; never construct identifiers from request strings.
• SELECT reads rows; DELETE is a write operation.

Use Deleting Records with PDO when its documented behavior matches the problem. Test the relevant edge cases in your own runtime before deploying it.