使用PHP连接多种数据库的实现代码(mysql,access,sqlserver,Oracle)

<?php  
$mysql_server_name='localhost'; 
//改成自己的mysql数据库服务器 
$mysql_username='root'; 
//改成自己的mysql数据库用户名 
$mysql_password='12345678'; 
//改成自己的mysql数据库密码 
$mysql_database='mycounter';
 //改成自己的mysql数据库名 
$conn=mysql_connect($mysql_server_name,
$mysql_username,$mysql_password,
$mysql_database);  
$sql='create database mycounter 
default character set gbk collate gbk_chinese_ci;  
';  
mysql_query($sql);  
$sql='create table `counter` 
(`id` int(255) unsigned not null 
auto_increment ,`count` int(255) 
unsigned not null default 0,primary key 
( `id` ) ) type = innodb;';  
mysql_select_db($mysql_database,$conn);  
$result=mysql_query($sql);  
//echo $sql;  
mysql_close($conn);  
echo "hello!数据库mycounter已经成功建立！";  
?>

<? 
$conn = new com("adodb.connection");  
$connstr = "driver={microsoft
 access driver (*.mdb)}; 
dbq=". realpath("data/db.mdb");  
$conn->open($connstr);  
$rs = new com("adodb.recordset");  
$rs->open("select *
 from szd_t",$conn,1,1);  
while(! $rs->eof) {  
$f = $rs->fields(1);  
echo $f->value;  
$rs->movenext();  
}  
?>

< ?php  
$myserver = localhost; //主机 
$myuser = sa; //用户名 
$mypass = password; //密码 
$mydb = northwind; //mssql库名 
$s = @mssql_connect($myserver,
 $myuser, $mypass)  
or die(couldnt connect to 
sql server on $myserver);  
$d = @mssql_select_db($mydb, $s)  
or die(couldnt open database $mydb);  
$query = select titleofcourtesy
+ +firstname+ +lastname as employee ;  
$query .= from employees ;  
$query .= where country=usa 
and left(homephone, 5) = (206);  
$result = mssql_query($query);  
$numrows = mssql_num_rows($result);  
echo < h1> . $numrows . row .
 ($numrows == 1 ? : s) . returned ;  
while($row = mssql_fetch_array($result))  
{  
echo < li> . $row[employee] . < /li>;  
}  
?>

<? 
if ($conn=ora_logon
("user@tnsname","password"))  
{ echo "success ! 
connected to database\n";  
}else  
{echo "failed ???? 
could not connect to database\n";}  
ora_logoff($conn);  
phpinfo();  
?>