PHP数据库增删改查 PHP源码操作MySQL CRUD教程

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检测连接
if ($conn->connect_error) {
  die("连接失败: " . $conn->connect_error);
}
echo "连接成功";
?>

<?php
$sql = "CREATE TABLE MyGuests (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL,
email VARCHAR(50),
reg_date TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
)";

if ($conn->query($sql) === TRUE) {
  echo "Table MyGuests created successfully";
} else {
  echo "创建数据表错误: " . $conn->error;
}
?>

<?php
$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com')";

if ($conn->query($sql) === TRUE) {
  $last_id = $conn->insert_id;
  echo "新记录插入成功。 最后插入的 ID 是: " . $last_id;
} else {
  echo "Error: " . $sql . "<br>" . $conn->error;
}
?>

<?php
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$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["firstname"]. " " . $row["lastname"]. "<br>";
  }
} else {
  echo "0 结果";
}
?>

<?php
$sql = "UPDATE MyGuests SET lastname='Smith' WHERE id=2";

if ($conn->query($sql) === TRUE) {
  echo "记录更新成功";
} else {
  echo "更新记录出错: " . $conn->error;
}
?>

<?php
$sql = "DELETE FROM MyGuests WHERE id=3";

if ($conn->query($sql) === TRUE) {
  echo "记录删除成功";
} else {
  echo "删除记录出错: " . $conn->error;
}
?>

<?php
$conn->close();
?>

<?php
// 预处理语句示例 (MySQLi)
$stmt = $conn->prepare("INSERT INTO MyGuests (firstname, lastname, email) VALUES (?, ?, ?)");
$stmt->bind_param("sss", $firstname, $lastname, $email);

// 设置参数并执行
$firstname = "John";
$lastname = "Doe";
$email = "john@example.com";
$stmt->execute();

$firstname = "Jane";
$lastname = "Doe";
$email = "jane@example.com";
$stmt->execute();

echo "新记录插入成功";

$stmt->close();
?>

<?php
try {
    $conn = new mysqli($servername, $username, $password, $dbname);
    $conn->set_charset("utf8"); // 设置字符集，避免中文乱码

    if ($conn->connect_error) {
        throw new Exception("数据库连接失败: " . $conn->connect_error);
    }

    // 执行数据库操作...

} catch (Exception $e) {
    error_log($e->getMessage()); // 记录错误日志
    echo "发生错误，请稍后重试。"; // 显示友好的错误信息
} finally {
    if ($conn) {
        $conn->close(); // 始终关闭连接
    }
}
?>

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

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);

    $sql = "INSERT INTO MyGuests (firstname, lastname, email)
    VALUES ('John', 'Doe', 'john@example.com')";
    // 使用 exec() ，因为没有结果返回
    $conn->exec($sql);
    echo "新记录插入成功";
    }
catch(PDOException $e)
    {
    echo $sql . "<br>" . $e->getMessage();
    }

$conn = null;
?>

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $stmt = $conn->prepare("SELECT id, firstname, lastname FROM MyGuests WHERE lastname=:lastname");
    $stmt->bindParam(':lastname', $lastname);
    $lastname = "Doe";
    $stmt->execute();

    // 设置结果为关联数组
    $stmt->setFetchMode(PDO::FETCH_ASSOC);

    foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) {
        echo $v;
    }
}
catch(PDOException $e) {
    echo "Error: " . $e->getMessage();
}
$conn = null;
echo "</table>";
?>