PHP7连接数据库的方法

<?php$serve = 'localhost:3306';$username = 'root';$password = 'admin123';$dbname = 'examples';$mysqli = new Mysqli($serve,$username,$password,$dbname);if($mysqli->connect_error){
	die('connect error:'.$mysqli->connect_errno);}$mysqli->set_charset('UTF-8'); // 设置数据库字符集$result = $mysqli->query('select * from customers');$data = $result->fetch_all(); // 从结果集中获取所有数据print_r($data);

 ?>

<?php$serve = 'localhost:3306';$username = 'root';$password = 'admin123';$dbname = 'examples';$link = mysqli_connect($serve,$username,$password,$dbname);mysqli_set_charset($link,'UTF-8'); // 设置数据库字符集$result = mysqli_query($link,'select * from customers');$data = mysqli_fetch_all($result); // 从结果集中获取所有数据print_r($data);

 ?>

<?php$serve = 'mysql:host=localhost:3306;dbname=examples;charset=utf8';$username = 'root';$password = 'admin123';try{ // PDO连接数据库若错误则会抛出一个PDOException异常
	$PDO = new PDO($serve,$username,$password);
	$result = $PDO->query('select * from customers');
	$data = $result->fetchAll(PDO::FETCH_ASSOC); // PDO::FETCH_ASSOC表示将对应结果集中的每一行作为一个由列名索引的数组返回
	print_r($data);} catch (PDOException $error){
	echo 'connect failed:'.$error->getMessage();}

 ?>