怎样用php mysql类操作数据库表

要使用PHP和MySQL类操作数据库表，首先确保已经安装了MySQL服务器和PHP的MySQL扩展（如MySQLi或PDO）。以下是使用MySQLi扩展操作数据库表的示例步骤：

1. 连接到MySQL数据库服务器：

$servername = "localhost"; // 服务器地址 $username = "your_username"; // 用户名 $password = "your_password"; // 密码 $dbname = "your_database"; // 数据库名  // 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"; 

2. 创建数据表：

$sql = "CREATE TABLE users (     id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,     username VARCHAR(30) NOT NULL,     email VARCHAR(50) NOT NULL,     password VARCHAR(255) NOT NULL )";  if ($conn->query($sql) === TRUE) {     echo "数据表创建成功"; } else {     echo "创建数据表错误: " . $conn->error; } 

3. 插入数据：

$username = "testuser"; $email = "testuser@example.com"; $password = password_hash("testpassword", PASSWORD_DEFAULT);  $sql = "INSERT INTO users (username, email, password) VALUES (?, ?, ?)";  $stmt = $conn->prepare($sql); $stmt->bind_param("sss", $username, $email, $password);  if ($stmt->execute() === TRUE) {     echo "新记录插入成功"; } else {     echo "Error: " . $sql . "<br>" . $conn->error; }  $stmt->close(); 

4. 查询数据：

$sql = "SELECT id, username, email, password FROM users"; $result = $conn->query($sql);  if ($result->num_rows > 0) {     // 输出每行数据     while($row = $result->fetch_assoc()) {         echo "id: " . $row["id"]. " - Name: " . $row["username"]. " - Email: " . $row["email"]. " - Password: " . $row["password"]. "<br>";     } } else {     echo "0 结果"; } $result->free(); 

5. 更新数据：

$id = 1; $new_username = "updated_username"; $new_email = "updated_email@example.com";  $sql = "UPDATE users SET username = ?, email = ? WHERE id = ?";  $stmt = $conn->prepare($sql); $stmt->bind_param("sss", $new_username, $new_email, $id);  if ($stmt->execute() === TRUE) {     echo "记录更新成功"; } else {     echo "Error: " . $sql . "<br>" . $conn->error; }  $stmt->close(); 

6. 删除数据：

$id = 1;  $sql = "DELETE FROM users WHERE id = ?";  $stmt = $conn->prepare($sql); $stmt->bind_param("i", $id);  if ($stmt->execute() === TRUE) {     echo "记录删除成功"; } else {     echo "Error: " . $sql . "<br>" . $conn->error; }  $stmt->close(); 

7. 关闭数据库连接：

$conn->close(); 

请注意，这只是一个简单的示例。在实际项目中，建议使用PHP框架（如Laravel或Symfony）和ORM（对象关系映射）库来操作数据库表，以提高代码的可维护性和安全性。