文件上传！！

刚做的,自己看吧,Path是要保存的文件地址
     $str="select * from $table1 where BigClass='$BigClass'";
     $result=mssql_query($str,$comm);
     $record=mssql_fetch_object($result);
     $Path=$record->Path;
     $BigClassID=$record->ID;
     if (is_uploaded_file($_FILES['filename']['tmp_name']))
      {
       $Path=$Path . chr(92). $_FILES['filename']['name'];//文件名
       $Path=addslashes($Path); //添加路径上的反斜线
       if(file_exists($Path))
        echo "<script>alert('已存在该文件名，请更改该文件名后再上传！');</script>";
       else
        {
         if(!copy($_FILES['filename']['tmp_name'], $Path))
          echo "<script>alert('文件拷贝错误！');</script>";
         else
          {
           $FileSize=$_FILES['filename']['size'];
           $datetime=time();
           $str="select * from $table3 where DataName='$DataName'";
           $result=mssql_query($str,$comm);
           $number=mssql_num_rows($result);
           if($result and $number>=1) //数据库中存在该记录
            {
             echo "<script>alert('错误，已存在该资源名称，请更改！');</script>";
             if(!unlink($Path)) //删除文件
              echo "<script>alert('删除文件错误！');</script>";
            }
           else //还不存在，则添加
            {
             $str="Insert INTO $table3
                      (DataName,Abstract,DateTime,DownNumber,FileSize,Path,UpName,UpEmail,ClassName,BigClass)
               Values ('$DataName','$Abstract','$datetime',0,'$FileSize','$Path','$UploadName','$UploadEmail','$SmallClass','$BigClassID')";
             $result=mssql_query($str,$comm); //写到数据库
             if(!$result) //写数据库错误
              {
               echo "<script>alert('写入数据库错误！');</script>";
               if(!unlink($Path))         //删除文件
                echo "<script>alert('删除文件错误！');</script>";
              }
             else
              {
               echo "<br><center><INPUT TYPE=BUTTON NAME=close value='上传成功,关闭窗口' onClick='window.close()'>";
               exit;
              }
            }
          }
        }
      }
     else
      {
       echo "<br>不是上传文件！<br>";
       exit;
      }