php连接mysql数据库的几种方法

1.最简单的方式

<?php
$con = mysql_connect("localhost","root","");
if (!$con)
 {
  die('Could not connect: ' . mysql_error());
 }
mysql_close($con);
?>

2.面向对象mysqli

<?php
$db = new PDO('mysql:host=localhost;dbname=test', 'root', '');
try {
 foreach ($db->query('select * from user') as $row){
     print_r($row);
  }
  $db = null;  //关闭数据库
} 
 catch (PDOException $e) {echo $e->getMessage();
}
?>

3.pdo连接mysql

<?php
$db = new PDO('mysql:host=localhost;dbname=test', 'root', '');
try {
    foreach ($db->query('select * from user') as $row){
        print_r($row);
    }
    $db = null;  //关闭数据库
} 
catch (PDOException $e) {
    echo $e->getMessage();
}
?>

4.ADODB连接mysql

<?php
require_once './adodb5/adodb.inc.php';
$conn = &ADONewConnection('mysql');
$conn->connect('localhost','root','','test');
$conn->Execute("set names utf8");
$res = $conn->Execute("select * from user");
if (!$res){
    echo $conn->ErrorMsg();
}else{
    var_dump($res);
}
?>