PHP 5 及以上版本建议使用以下方式连接 MySQL :

• MySQLi extension （"i" 意为 improved）
• PDO (PHP Data Objects)（支持多种数据库）

1. MySQLi

1.1. MySQLi的安装

安装完php-mysql包时会默认安装mysqli扩展，因此确保系统安装好该包即可

yum install- y php-mysql

1.2. php连接Mysqli

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

// 创建连接
$conn = mysqli_connect($servername, $username, $password);

// 检测连接
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
echo "连接成功";
?>

1.3. 创建数据库

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

// 创建连接
$conn = mysqli_connect($servername, $username, $password);
// 检测连接
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

// 创建数据库
$sql = "CREATE DATABASE myDB";
if (mysqli_query($conn, $sql)) {
    echo "数据库创建成功";
} else {
    echo "Error creating database: " . mysqli_error($conn);
}

mysqli_close($conn);
?>

1.4. 创建数据表

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

// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);
// 检测连接
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

// 使用 sql 创建数据表
$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
)";

if (mysqli_query($conn, $sql)) {
    echo "数据表 MyGuests 创建成功";
} else {
    echo "创建数据表错误: " . mysqli_error($conn);
}

mysqli_close($conn);
?>

1.5. 插入数据

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

// 创建链接
$conn = mysqli_connect($servername, $username, $password, $dbname);
// 检查链接
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com');";
$sql .= "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('Mary', 'Moe', 'mary@example.com');";
$sql .= "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('Julie', 'Dooley', 'julie@example.com')";

if (mysqli_multi_query($conn, $sql)) {
    echo "新记录插入成功";
} else {
    echo "Error: " . $sql . "<br>" . mysqli_error($conn);
}

mysqli_close($conn);
?>

2. PDO

2.1. PDO的安装

编译包进行安装：

参考：https://www.php.net/manual/en/pdo.installation.php#114683

使用yum仓库进行安装：

yum install php-pdo

2.2. php连接PDO

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

try {
    $conn = new PDO("mysql:host=$servername;", $username, $password);
    echo "连接成功"; 
}
catch(PDOException $e)
{
    echo $e->getMessage();
}
?>

2.3. 创建数据库

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

try {
    $conn = new PDO("mysql:host=$servername", $username, $password);

    // 设置 PDO 错误模式为异常
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $sql = "CREATE DATABASE myDBPDO";

    // 使用 exec() ，因为没有结果返回
    $conn->exec($sql);

    echo "数据库创建成功<br>";
}
catch(PDOException $e)
{
    echo $sql . "<br>" . $e->getMessage();
}

$conn = null;
?>

2.4. 创建数据表

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

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // 设置 PDO 错误模式，用于抛出异常
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 使用 sql 创建数据表
    $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
    )";

    // 使用 exec() ，没有结果返回 
    $conn->exec($sql);
    echo "数据表 MyGuests 创建成功";
}
catch(PDOException $e)
{
    echo $sql . "<br>" . $e->getMessage();
}

$conn = null;
?>

2.5. 插入数据

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

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 开始事务
    $conn->beginTransaction();
    // SQL 语句
    $conn->exec("INSERT INTO MyGuests (firstname, lastname, email) 
    VALUES ('John', 'Doe', 'john@example.com')");
    $conn->exec("INSERT INTO MyGuests (firstname, lastname, email) 
    VALUES ('Mary', 'Moe', 'mary@example.com')");
    $conn->exec("INSERT INTO MyGuests (firstname, lastname, email) 
    VALUES ('Julie', 'Dooley', 'julie@example.com')");

    // 提交事务
    $conn->commit();
    echo "新记录插入成功";
}
catch(PDOException $e)
{
    // 如果执行失败回滚
    $conn->rollback();
    echo $sql . "<br>" . $e->getMessage();
}

$conn = null;
?>