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php数据库实现

2026-01-15 12:17:28PHP

PHP 连接 MySQL 数据库

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("连接失败: " . $conn->connect_error);
}
echo "连接成功";
?>

执行 SQL 查询

使用 mysqli_query 执行 SQL 查询：

$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 结果";
}

插入数据

使用预处理语句防止 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 "新记录插入成功";
$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 "记录更新成功";
$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 "记录删除成功";
$stmt->close();

关闭数据库连接

完成操作后关闭连接：

$conn->close();

使用 PDO 连接数据库

PDO 是另一种数据库连接方式，支持多种数据库：

$dsn = "mysql:host=localhost;dbname=database_name";
$username = "username";
$password = "password";

try {
    $pdo = new PDO($dsn, $username, $password);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "连接成功";
} catch(PDOException $e) {
    echo "连接失败: " . $e->getMessage();
}

PDO 查询示例

使用 PDO 执行查询：

$stmt = $pdo->query("SELECT id, name, email FROM users");
while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
    echo "id: " . $row['id'] . " - Name: " . $row['name'] . " - Email: " . $row['email'] . "<br>";
}

PDO 预处理语句

PDO 预处理语句示例：

$stmt = $pdo->prepare("INSERT INTO users (name, email) VALUES (:name, :email)");
$stmt->bindParam(':name', $name);
$stmt->bindParam(':email', $email);

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

错误处理

设置错误处理模式：

$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

事务处理

使用事务确保数据完整性：

$pdo->beginTransaction();
try {
    $pdo->exec("INSERT INTO users (name, email) VALUES ('User1', 'user1@example.com')");
    $pdo->exec("INSERT INTO users (name, email) VALUES ('User2', 'user2@example.com')");
    $pdo->commit();
} catch (Exception $e) {
    $pdo->rollBack();
    echo "事务失败: " . $e->getMessage();
}

php数据库实现