อยากรู้ รูปแบบ การเขียน code php การลบข้อมูล แก้ไขข้อมูล

<?
include "connect.php";
$page=$_GET['page'];
if ($page=="") {
  $page=1;
}
$each=10;

$sql_product = "SELECT * FROM tb_o , tb_stock";
$result_product = mysql_query($sql_product);
$totals = mysql_num_rows($result_product);

$totalpages=ceil($totals/$each);
$goto = ($page-1)*$each;

$sql_product = "SELECT * FROM tb_o ORDER BY id ASC ";
$result_product = mysql_query($sql_product);

$sql="SELECT MAX(data) AS data FROM tb_o";
$result=mysql_query($sql);
$dbarr=mysql_fetch_array($result);

  if ($num=="0") {
    $total ="";
  } else {	
    $total=$dbarr_product['id_no'] +1;
    if ($total<10) {
      $total="000" .$total;
    } elseif ($total<100) {
      $total="00".$total;
    } elseif ($total<1000){
      $total="0" .$total;
    }
  }	
?>

<table width="900" border="0" align="center" cellpadding="1" cellspacing="1" bordercolordark="#FFFFFF">
  <tr>
    <td colspan="9"  bgcolor="#FFCCCC" align="center"><b>รายการ</b></td>
  </tr>
  <tr bgcolor="#FFFFCC">
    <td width="115" align="center">เลขที่</td>		
    <td width="500" align="center">รายการ</td>
	<td width="206" align="center">จำนวน</td>
	<td width="206" align="center">ราคา</td>
	<td width="206" align="center">เบิก</td>
	<td width="206" align="center">เหลือ</td>
    <td width="73" align="center">แก้ไข</td>		
    <td width="77" align="center">ลบ</td>		  
  </tr>	
<?
while ($dbarr_product = mysql_fetch_array($result_product)) {
?>	
<? $sql3=mysql_query("update td_o set m_amount = m_amount - $m_out_amount where m_id=$m_id2");
?>
  <tr bgcolor="#F4F4F4">
    <td align="center"><? echo $dbarr_product['number'];?></td>
    <td align="center"><? echo $dbarr_product['data'];?></td> 
	<td align="center"><? echo $dbarr_product['count'];?></td>
	<td align="center"><? echo $dbarr_product['price'];?></td>
	<td align="center"><? echo $sql3;?></td>
	<td align="center"><? echo $dbarr_product['rest'] ;?></td>
    <td align="center">[ <a href="admin.php?show=edit"; ]>แก้ไข</a> ]</td>
    <td align="center">[ <a href="admin.php?show=<? echo $id; ?>" onClick="return Conf<? echo "$id=['id']"; ?>(this)">ลบ</a>]</td>
  </tr>
<?
}
?>				
  <tr bgcolor="#F4F4F4" >
    <td colspan="10" align="right">&nbsp;</td>
  </tr>	
</table>

<form name="frmPackage" method="post" action="chkstock.php" enctype="multipart/form-data">
<table width="500" border="0" align="center" cellpadding="0" cellspacing="0" bordercolordark="#FFFFFF">
  <tr>
    <td bgcolor="#FFCCCC" align="center"><b>เพิ่มข้อมูล</b></td>
  </tr>
  <tr>
    <td>
      <table width="700" border="0" align="center" cellpadding="5" cellspacing="1">
        <tr bgcolor="#F4F4F4">
          <td width="50%" align="left">เลขที่
            <INPUT maxLength=10 name=number  size="8"></td>
          <td width="50%"calign="left">แผนก
             <select name="Deparmentname">
		      	<option value="0">กรุณาเลือกแผนก</option>
      			<?
				$sql="select * from tb_adddepartment ";
				$result = mysql_query($sql);
					while($dbarr_product=mysql_fetch_array($result)) {
						echo "<option value=$dbarr_product[id_no]>$dbarr_product[Departmentname]</option>";
					}
				?>
            </select></td>  
        </tr>
        <tr bgcolor="#F4F4F4">
          <td colspan="4" align="left">รายการ 
            <input maxlength="150" name="data" size="80"></td>
        </tr>		
        <tr>
          <td align="left">ราคา 
            <input maxlength="50" name="price" size="8"> 
            บาท จำนวน 
              <input maxlength="50" name="count" size="8" /></td>
          <td align="left">ไฟล์รูปภาพ <input type="file" name="photo"><input type="hidden" name="MAX_FILE_SIZE" value="100000"></td>
        </tr>			
        <tr bgcolor="#F4F4F4">
          <td colspan="2" align="left">หมายเหตุ<br>
              <textarea name="message" cols="100" rows="30"></textarea></td>
        </tr>												
        <tr bgcolor="#F4F4F4">
          <td colspan="6" align="center">
          	<input type="submit" name="submit" value="บันทึก">
            <input type="reset" name="Reset" value="ล้างข้อมูล">
            <input name="cid" type="hidden" value="<?=$total;?>">          </td>
        </tr>
      </table>
    </td>
  </tr>
</table>
</form>