APEX

I'm new to Apex and am just assessing if we can make use of it, mainly for reporting functionality in our existing web based application.

We have a schema that holds all of our procedures, packages, functions etc and they all have AUTHID = CURRENT_USER so each user can have their own set of tables in their own schema.

I want to be able to create reports in Apex that will then report on the users table in their own schema but I can't quite work out how Apex actually works. Can I tell something in Apex to use AUTHID = CURRENT_USER?

We used Webdb many years ago and that created the runtime package for all the forms and reports but I can't see anything that Apex creates so I assume it stores all the code in a table somewhere?

Thanks
Robert