php mySQL实现
PHP 与 MySQL 实现数据库操作
PHP 与 MySQL 的结合是 Web 开发中常见的数据库操作方式。以下是实现数据库连接、查询、插入、更新和删除的基本方法。
数据库连接
使用 mysqli 扩展连接 MySQL 数据库：
<?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("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
?>查询数据
执行 SELECT 查询并获取结果：
$sql = "SELECT id, name, email FROM users";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
echo "id: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
}
} else {
echo "0 results";
}插入数据
使用预处理语句插入数据以防止 SQL 注入：
$stmt = $conn->prepare("INSERT INTO users (name, email) VALUES (?, ?)");
$stmt->bind_param("ss", $name, $email);
$name = "John Doe";
$email = "john@example.com";
$stmt->execute();
echo "New records created successfully";
$stmt->close();更新数据
更新数据库中的记录：
$stmt = $conn->prepare("UPDATE users SET email=? WHERE name=?");
$stmt->bind_param("ss", $email, $name);
$email = "newemail@example.com";
$name = "John Doe";
$stmt->execute();
echo "Record updated successfully";
$stmt->close();删除数据
从数据库中删除记录：
$stmt = $conn->prepare("DELETE FROM users WHERE name=?");
$stmt->bind_param("s", $name);
$name = "John Doe";
$stmt->execute();
echo "Record deleted successfully";
$stmt->close();关闭连接
完成数据库操作后关闭连接：
$conn->close();使用 PDO 实现数据库操作
PDO（PHP Data Objects）是另一种数据库访问抽象层，支持多种数据库。
数据库连接
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo "Connected successfully";
} catch(PDOException $e) {
echo "Connection failed: " . $e->getMessage();
}
?>查询数据
$stmt = $conn->prepare("SELECT id, name, email FROM users");
$stmt->execute();
$result = $stmt->fetchAll(PDO::FETCH_ASSOC);
foreach ($result as $row) {
echo "id: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
}插入数据
$stmt = $conn->prepare("INSERT INTO users (name, email) VALUES (:name, :email)");
$stmt->bindParam(':name', $name);
$stmt->bindParam(':email', $email);
$name = "John Doe";
$email = "john@example.com";
$stmt->execute();
echo "New records created successfully";更新数据
$stmt = $conn->prepare("UPDATE users SET email=:email WHERE name=:name");
$stmt->bindParam(':email', $email);
$stmt->bindParam(':name', $name);
$email = "newemail@example.com";
$name = "John Doe";
$stmt->execute();
echo "Record updated successfully";删除数据
$stmt = $conn->prepare("DELETE FROM users WHERE name=:name");
$stmt->bindParam(':name', $name);
$name = "John Doe";
$stmt->execute();
echo "Record deleted successfully";关闭连接
$conn = null;安全性注意事项
- 使用预处理语句防止 SQL 注入。
- 避免直接拼接 SQL 查询字符串。
- 对用户输入进行验证和过滤。
- 使用 HTTPS 保护数据传输安全。
以上方法涵盖了 PHP 与 MySQL 数据库交互的基本操作，适用于大多数 Web 开发场景。
