PHP 连接数据库

<?php
error_reporting(E_DEPRECATED);
//定义常量
define ("DB_HOST","localhost");
define ("DB_USER","root");
define ("DB_PASS","");
define ("DB_DATABASENAME","jia");
define ("DB_TABLENAME","students");
//数据库表的列名
$dbcolarry = array (
    "id",
    "stuname",
    "sex",
    "age",
    "tel"        
    );
//php里面的变量可以不用类型
$link = mysql_connect(DB_HOST,DB_USER,DB_PASS) or die("connection error".mysql_error());
echo "$link";
$flag=mysql_select_db(DB_DATABASENAME,$link);
mysql_query ( "set names gbk" );//设置编码方式
if($flag){
    echo "数据库连接成功！";
    }
    //$sql = "select * from students";
    $result = mysql_query ( "select * from students",$link);
    echo $result;
    do{
        $info = mysql_fetch_array ($result);
        if ($info){
            echo $info['stuname'];     //注意区分大小写以及表的名称，编码是否统一是GBK
        }
    } while ($info)    
}
?>