pg_bofh is a simple extension providing a planner hook example on how to analyze incoming queries to forbid some of them.

How to use

Compile and install it:

make && sudo make install

Add it to the shared_preload_libraries parameter in postgresql.conf, and restart your server:

shared_preload_libraries='pg_bofh'

From now on, any query with no "WHERE" clause will raise an error instead of being executed.