It's quite simple. As ever, you need to simply think through the requirements.
What do we know?
* You can send information to the exact same page as you are using to display information
* You can process ASP code before showing any HTML code.
What can we do?
* Setup the link to go to the same page, but have some parameters that we can check
* Check for the edit and so show an edit form rather than the whole page
---- If Request.Querysting("edit") = "true" AND Len(Request.Querysting("itemid")) > 0 Then
* When the edit form is submitted, check for THIS, do the database updates then show the normal table.
Think about how you might do what you want to do, code something up then come back for help on why it doesn't work (or maybe it will?), then we can help you. If you don't try to do something yourself then all that will happen is that other people end up building your application for you in a piecemeal fashion, and you end up with an application that is a right dog's dinner to maintain. (And you don't actually learn anything).
It doesn't have to be a link - it could be a button, or radio button or even a checkbox. However there needs to be SOME way of identifying WHICH record is to be edited. And since each record is defined by its itemid then that's what you need to use.
I've already outlined a process, so that's where you start.