PDO Best Practices

Always use prepared statements, set error mode to exceptions, avoid persistent connections in web apps, and wrap PDO in a repository class to isolate database access.

Example

<?php
// Repository pattern wrapping PDO
class UserRepository {
    public function __construct(private PDO $pdo) {}

    public function find(int $id): ?array {
        $stmt = $this->pdo->prepare("SELECT * FROM users WHERE id = :id LIMIT 1");
        $stmt->execute(["id" => $id]);
        return $stmt->fetch() ?: null;
    }

    public function findAll(int $limit = 50, int $offset = 0): array {
        $stmt = $this->pdo->prepare("SELECT * FROM users ORDER BY id LIMIT :limit OFFSET :offset");
        $stmt->bindValue(":limit", $limit, PDO::PARAM_INT);
        $stmt->bindValue(":offset", $offset, PDO::PARAM_INT);
        $stmt->execute();
        return $stmt->fetchAll();
    }
}

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Pro Tip

Inject PDO into repositories as a dependency — never call new PDO() inside a class method.

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