Your links are not passing the ID as a URL variable.
the link needs to be set up so that the ID is passed as a URL variable
you can use the recordset binding for the ID column in the link to pass the URL variable.
on the update and delete pages, the recordset should be configured to use the URL variable as the filter.
see the database starter kit tutorial for more details:
it was written for MySQL, but the concept is the same.