一、mysql_connect函数连接：

<?php
$dblink=mysql_connect("localhost","root","");
mysql_select_db("business",$dblink);
mysql_query("set names gbk");
?>

二、mysqli_connect函数连接：

<?php
$dblink=mysqli_connect("localhost","root","","business");
if(!$dblink){
echo "连接数据库失败!!";
echo mysqli_connect_error();
exit(); }
mysqli_query($dblink,"set names gbk");
?>
备注：使用该函数连接数据库，需要将php.ini文中中";extension=php_mysqli.dll"中的分号";"去掉，然后从新启动Apache服务器。

三、面向对象方式连接数据库：

1、conn_class.php：
<?php
class con
{
private $hostname;
private $username;
private $userpwd;
private $databasename;
public $conn;
public function __construct($x,$y,$m,$n)
{
$this->hostname=$x;
$this->username=$y;
$this->userpwd=$m;
$this->databasename=$n;
}
public function getcon()
{
$this->conn=mysql_connect($this->hostname,$this->username,$this->userpwd);
mysql_select_db($this->databasename,$this->conn);
mysql_query("set names GBK");
}
}
?>
2、config.php：
<?php
include_once('conn_class.php')
$conndb=new con("localhost","root","","business");
$conndb->getcon();
if ($conndb == null)
{
echo "数据库连接失败
";
exit();
}
?>
备注：使用此连接方式，需要在SQL执行语句后加",$conndb->conn"，如：
<?php
include_once('config.php');
$sql=mysql_query("select * from `business_hezuo` order by `hezuo_rank` asc",$conndb->conn);
$info=mysql_fetch_array($sql);
if($info==false){
echo "暂无信息!";
}else{
do{
?>