How to debug issue where LaTeX refuses to produce more than 7 pages?

You are getting a warning in the log:

(\end occurred inside a group at level 1)

### simple group (level 1) entered at line 70 ({)
### bottom level 

This indicates something is wrong. And if one looks at line 70 one can see the culprit:

{\let\clearpage\relax\chapter*{Databases exercise 1}

You are redefining \clearpage to do nothing but don't close the group as a brace is missing, and so \clearpage is missing at end document (where it is really needed).