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();  
?>