php--adodb如何连接数据库

<?php
//下载后，放置在根目录
include_once ("adodb-5.20.17/adodb5/adodb.inc.php");
//数据库用户名，密码，库名
$host = "localhost";
$user = "root";
$pass = "mysql123";
$db = "world";
//连接数据库的类型，旧版写mysql，新版写mysqli
$conn = ADONewConnection('mysqli');

$conn->Connect($host,$user,$pass,$db);
//调试模式
$conn->debug = true;

$conn->Execute("SET NAMES gb2312");

$sql = "select name,region from country where continent='Asia' limit 0,15";
//执行sql
$result = $conn->Execute($sql);

if($result == false)
{
    echo "<pre>".$conn->ErrorMsg()."</pre>";
}
else
{
    //显示数据
    $table = "<table border='1'><tr><th>Name</th><th>Region</th>";
    while($row = $result->FetchRow())
    {
        $table .= "<tr><td>".$row[0]."</td><td>".$row[1]."</td></tr>";
    }
    $table .= "</table>";
    echo $table;
}
//关闭数据库
$conn->close();