Rewrite Url

Hi,
I have link with like http://www.site.com/event=1 when this link is clicked it will be redirect to post-archive page. but i don’t receive the uri in the post_archive .
where in the url event is a post_id which i want show the the post_archive page (just one post)

Please tell how to do
I tried using a session it is working but I think it can be done in many ways.