php数据库如何实现增删改查 php数据库基本操作的综合教程

$host = 'localhost';
$dbname = 'test_db';
$username = 'root';
$password = '123456';
<p>try {
$pdo = new PDO("mysql:host=$host;dbname=$dbname;charset=utf8", $username, $password);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
die("连接失败: " . $e->getMessage());
}</p>

$sql = "INSERT INTO users (name, email, age) VALUES (?, ?, ?)";
$stmt = $pdo->prepare($sql);
$name = '张三';
$email = 'zhangsan@example.com';
$age = 25;
<p>if ($stmt->execute([$name, $email, $age])) {
echo "插入成功，新ID：" . $pdo->lastInsertId();
}</p>

$sql = "INSERT INTO users (name, email, age) VALUES (:name, :email, :age)";
$stmt = $pdo->prepare($sql);
$stmt->execute([':name' => $name, ':email' => $email, ':age' => $age]);

// 查询所有用户
$sql = "SELECT * FROM users";
$stmt = $pdo->query($sql);
$users = $stmt->fetchAll(PDO::FETCH_ASSOC);
<p>foreach ($users as $user) {
echo "姓名：{$user['name']}，邮箱：{$user['email']}<br>";
}</p><p>// 查询单条记录
$sql = "SELECT * FROM users WHERE id = ?";
$stmt = $pdo->prepare($sql);
$stmt->execute([1]);
$user = $stmt->fetch(PDO::FETCH_ASSOC);</p><p>if ($user) {
echo "找到用户：{$user['name']}";
} else {
echo "用户不存在";
}</p>

$sql = "UPDATE users SET name = ?, email = ? WHERE id = ?";
$stmt = $pdo->prepare($sql);
$newName = '李四';
$newEmail = 'lisi@example.com';
$id = 1;
<p>if ($stmt->execute([$newName, $newEmail, $id])) {
echo "更新成功，影响行数：" . $stmt->rowCount();
}</p>

$sql = "DELETE FROM users WHERE id = ?";
$stmt = $pdo->prepare($sql);
$id = 1;
<p>if ($stmt->execute([$id])) {
echo "删除成功，影响行数：" . $stmt->rowCount();
} else {
echo "删除失败";
}</p>