CiviCRM. Drupal. modifications to CiviCRM module

Currently , we have CivicCRM , a module for Drupal, installed into ElectoralReg.com. It is out of the box. No changes If we have 4 users, and those for users upload constituents a, b, c and d. then user 1 can see all constituents. user 2 can see al constituents. and so on... we require it so that user 1 can only see the constituents that they upload. user 2 can only see their own constituents and so on we assume its a simple piece of code at the end of the select statement stating "where user-id = user 1" we also require so that user 1 can only see user 1's donations. user 1 cannot see user 2's donations and so on regarding queries, again, users can only see their own queries... no one elses if u require a testimonial from someone else that has worked with us. please let me know there is also a main admin for the site, we expect the admin to be able to see everything that they can see now. so the changes are only with the users. any questions, ask us.