Statistics on database structure changes

Hello,



I need to collect some information on changes in database structure for 
further analysis. I'm interested in the following information:
- new and dropped tables and views;
- new and dropped table columns;
- new and dropped primary and foreign keys;
- timestamp of such a change;
- affected table and probably columns for every change.

Are there any other "native" ways to do this (to export certain 
successfully(!) finished queries) without parsing PostgreSQL's log 
on-the-fly or modification of the backend source?



Thank you.


Sincerely yours,
Aleksey.