php数据库连接实现
PHP 连接 MySQL 数据库的方法
使用 MySQLi 面向对象方式连接
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";
// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);
// 检查连接
if ($conn->connect_error) {
die("连接失败: " . $conn->connect_error);
}
echo "连接成功";
?>使用 MySQLi 过程化方式连接
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";
// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);
// 检查连接
if (!$conn) {
die("连接失败: " . mysqli_connect_error());
}
echo "连接成功";
?>使用 PDO 方式连接
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// 设置 PDO 错误模式为异常
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo "连接成功";
}
catch(PDOException $e) {
echo "连接失败: " . $e->getMessage();
}
?>执行查询操作
MySQLi 面向对象查询
$sql = "SELECT id, name FROM users";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
}
} else {
echo "0 结果";
}PDO 查询示例
$stmt = $conn->prepare("SELECT id, name FROM users");
$stmt->execute();
// 设置结果集为关联数组
$result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
foreach($stmt->fetchAll() as $row) {
echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
}关闭数据库连接
MySQLi 关闭连接
$conn->close();PDO 关闭连接
$conn = null;安全注意事项
使用预处理语句防止SQL注入
// MySQLi 预处理
$stmt = $conn->prepare("INSERT INTO users (name, email) VALUES (?, ?)");
$stmt->bind_param("ss", $name, $email);
// PDO 预处理
$stmt = $conn->prepare("INSERT INTO users (name, email) VALUES (:name, :email)");
$stmt->bindParam(':name', $name);
$stmt->bindParam(':email', $email);错误处理最佳实践
在生产环境中关闭错误显示
ini_set('display_errors', 0);
error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED);记录错误到日志文件
ini_set('log_errors', 1);
ini_set('error_log', '/path/to/php-error.log');
