Is it possible to recreate a database structure using the downloaded pages as
reference? 

I can see the pages are coded and all entries from (obviously a database) the
site exist as pages, rather than db entries. I understand that only the owner
can access the database, but is there a way to create a database from the
downloaded pages? 

The reason is that i can see a site that has a design almost exactly the same
as i want for mine, and to save time, i thought it might be possible to
download a site, and make modifications to my requirements.