how to unset session as well as entry from tables
<p>i m adding an book detail in a page(book_detail.php),
 when i add book information ,i m also adding offers and addons via iframe( using lightwindow.js) related with that book and i saved their id;s in 2 session array. 
 if someone add 2 addons and 3 offers related to that books, i store those addons_is and offer_id in session and when i fill the all detail regarding that book,on the same time i add 
addons_is and offer_id in the database in same row.
like</p>

<pre><code>book_id|book_name|book_price|book_addons|book_offers|
 1     | php     | 100      |10,11,     | 17,18,19
</code></pre>

<p>where 10,11 from table_addon where that addon detail is saved
and 17,18,19 is from table_offers where offer details are saved</p>

<p><strong>now my question is:</strong>
   if someone add 2 offers and 3 addons with their detail, and does not go to submit that page( means he does not add details of that book) and go back, then how do i delete that addons and offers from both of tables.means i want to reset session array as well as the entry from both of table , if someone comes again to add new book detail.</p>

<p>i can not reset session when use comes first time , because on adding addons via iframe , page refresh automatically, so it is not possible to reset session on page load</p>
