intermediate 14 min read

PDO & Database Access

PDO connections, prepared statements, transactions, and result fetching.

PDO Database Access

// Connect
\$pdo = new PDO(
    "mysql:host=localhost;dbname=test",
    \$user, \$password,
    [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]
);

// Prepared statement (prevents SQL injection)
\$stmt = \$pdo->prepare(
    "SELECT * FROM users WHERE email = :email"
);
\$stmt->execute(['email' => \$email]);
\$user = \$stmt->fetch(PDO::FETCH_ASSOC);

// Named vs positional
\$stmt = \$pdo->prepare(
    "INSERT INTO users (name, email) VALUES (?, ?)"
);
\$stmt->execute([\$name, \$email]);

// Transactions
\$pdo->beginTransaction();
try {
    // multiple queries
    \$pdo->commit();
} catch (Exception \$e) {
    \$pdo->rollBack();
}

Examples

<?php
// Simulated PDO example
function getUserByEmail(PDO $pdo, string $email): array|false {
    $stmt = $pdo->prepare('SELECT * FROM users WHERE email = ?');
    $stmt->execute([$email]);
    return $stmt->fetch(PDO::FETCH_ASSOC);
}

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