How to connect php to MSSQL

  $conn=mssql_connect("实例名或者服务器IP","用户名","密码");

  //测试连接
  if($conn)
  {
  echo "连接成功";
  }

 mssql_select_db("dbname");

$rs = mssql_query("select top 1 id,username from tbname",$conn);
// 或者直接执行update,insert等语句,可以不用为返回结果赋值
mssql_query("update tbname set username='niunv' where id=1");

 echo mssql_num_rows($rs);

 if($row=mssql_fetch_array($rs))
  {
  $id = $row[0];//获取ID字段值
  $username = $row[1];//获取username字段值
  }

  mssql_query("insert into tbname(username) values ('nv')",$conn); 
  $rs = mssql_query("select @@IDENTITY as id",$conn);
  if($row=mssql_fetch_array($rs))
  {
  echo $row[0];
  }

 mssql_free_result($rs);

 mssql_close($conn);

 <?php 
 /** 
 *mssql 数据库连接类 
 **/ 
 class SQL{ 
 
 var $server; 
 var $userName; 
 var $passWord; 
 var $dataBase; 
 
 var $linkID = 0; 
 var $queryResult; 
 var $lastInsertID; 
 
 var $pageNum = 0;//分页用---共有几条数据 
 var $ER; 
 
 /** 
 *构造函数 
 **/ 
 function  SQL($Server=&#39;&#39;,$UserName=&#39;&#39;,$PassWord=&#39;&#39;,$DataBase=&#39;&#39;){ 
 $this->server = $Server; 
 $this->userName = $UserName; 
 $this->passWord = $PassWord; 
 $this->dataBase = $DataBase; 
 } 
 /** 
 *数据库连接 
 **/ 
 function db_connect(){ 
 $this->linkID = mssql_pconnect($this->server,$this->userName,$this->passWord); 
 if(!$this->linkID){ 
 $this->ER = "db_connect($this->server,$this->userName,$this->passWord) error"; 
 return 0; 
 } 
 if (!mssql_select_db($this->dataBase,$this->linkID)) { 
 $this->ER = "mssql_select_db($this->dataBase,$this->lastInsertID) error"; 
 return 0; 
 } 
 return $this->linkID; 
 } 
 
 /**public 
 *  function: Check the database, if exist then select 
 *  exist: return 1 
 *  not exist: return 0 
 */ 
 function selectDatabase(){ 
 if(mssql_select_db($this->dataBase)) 
 return 1; 
 else 
 return 0; 
 } 
 
 /** 
 *数据操作 
 **/ 
 function  query($Str){ 
 if ($this->linkID == 0) { 
 $this->ER = "数据库还没有连接！！"; 
 } 
 
    $this->queryResult = mssql_query($Str);  
 //$this->queryResult = mssql_query($Str,$this->linkID); 
 if (!$this->queryResult) { 
  
 
 $this->ER = "$Str.没有操作成功,query error！！"; 
 return 0;//****************对于php 4.3.9以上版本的错误用1 
 } 
 return $this->queryResult; 
 } 
 
 /** 
 *数据获取 
 **/ 
 function fetch_array($result){ 
 if($result != "") $this->queryResult = $result; 
 $rec =mssql_fetch_array($this->queryResult); 
 
 if(is_array($rec)){ 
 return $rec; 
 
 } 
 
 //$this->ER = "没有获取数据！"; 
 return 0; 
 } 
 
 /**public 
 *  function: Free the Query Result 
 *  success return 1 
 *  failed: return 0 
 */ 
 function freeResult($result=""){ 
 if($result != "") $this->queryResult = $result; 
 return mssql_free_result($this->queryResult); 
 } 
   
 /** 
 *获取影响的的行数 
 *获取操作过的行数 
 **/ 
 function num_rows($result=""){ 
 if ($result != "") { 
 $this->queryResult = $result; 
 $row = mssql_num_rows($this->queryResult); 
 return $row; 
 } 
 } 
   
 /** 
 *获取查询结果---多个 
 **/ 
 function result_ar($str=&#39;&#39;){ 
 if (empty($str)) { 
 return 0; 
 } 
 $back = array(); 
 $this->queryResult = $this->query($str); 
 
 while ($row = $this->fetch_array($this->queryResult)) { 
 $back[] = $row; 
 } 
 return $back; 
 } 
 
 /** 
 *数据库信息分页 
 *$Result 数据库操作 
 *str ==sql语句  
 *page ==第几页 
 *showNum ==显示几页 
 */ 
 function page($Str,$Page=0,$ShowNum=5){ 
 $back = array();//返回数据 
 $maxNum = 0; 
 if ($Str == "") { 
 $this->ER = "没有数据"; 
 return  0; 
 } 
 $this->queryResult = $this->query($Str); 
 if($this->queryResult){ 
 if($Page==""){ 
 $nopa=0; 
 }else{ 
 $nopa = ($Page-1)*$ShowNum; 
 if ($nopa<0) { 
 $nopa = 0; 
 } 
 } 
 $maxNum=$this->num_rows($this->queryResult); 
 $k=0; 
 $i=0; 
 $dd=$this->fetch_array($this->queryResult); 
 
 while($dd&&$nopa<=$maxNum&&$i<$ShowNum){ 
 if($nopa >= $maxNum)  $nopa = $maxNum; 
 mssql_data_seek($this->queryResult,$nopa); 
 
 $row=$this->fetch_array($this->queryResult); 
 
 $nopa++; 
 $i++; 
 $back[] = $row; 
 
 if ($nopa >=$maxNum) { 
 break; 
 } 
 } 
 } 
 $this->pageNum = $maxNum; 
 return $back; 
 } 
 
 /** 
 *分页的html页码 
 */ 
 function  page_html($DataNum=0,$Page=1,$ShowNum=3,$web,$Post=&#39;&#39;){ 
 if ($DataNum == 0) { 
 $back =  "没有要查询的数据"; 
 }else { 
 if ($ShowNum<=0) { 
 $ShowNum = 3; 
 } 
 if ($Page<=0) { 
 $Page = 1; 
 } 
 if (empty($web)) { 
 $web = "#"; 
 } 
 $pageNum = ceil($DataNum/$ShowNum); 
 if ($Page <= 1) { 
 $top =  "首页<<"; 
 }else { 
 $top = "<a href=&#39;".$web."?page=0&".$Post."&#39; target=&#39;_self&#39;>首页<< </a>"; 
 } 
 if ($Page !==1) { 
 $upPage =  "<a href=&#39;".$web."?page=".($Page-1)."&".$Post."&#39; target=&#39;_self&#39;>上一页</a>"; 
 }else { 
 $upPage = "上一页"; 
 } 
 if ($Page < $pageNum) { 
 $downPage = "<a href=&#39;".$web."?page=".($Page+1)."&".$Post."&#39; target=&#39;_self&#39;>下一页</a>"; 
 }else { 
 $downPage = "下一页"; 
 } 
 if ($Page == $pageNum) { 
 $foot = ">>尾页"; 
 }else { 
 $foot = "<a href=&#39;".$web."?page=".$pageNum."&".$Post."&#39; target=&#39;_self&#39;> >>尾页</a>"; 
 } 
 
 $back = <<<EOT 
 
 共 $pageNum 页    
 第 $Page/$pageNum 页 $top   $upPage   $downPage    $foot 
 EOT; 
 } 
 return $back; 
 } 
 }//end class 
 ?>