Not long ago, I posted a list of DBD modules that do not require you to have a separate RDBMS. Today I note Python moving in a similar direction, including doing some work with SQLite. Interesting that as folks here keep saying they'd like to see more done with SQLite (Slash on SQLite! Bundle it with Perl and Perl will include a complete database! etc., etc.), Python folks are noticing the same need.
For some time now, I've been saying I'd like to implement a complete RDBMS in Perl. My coworkers always said I was crazy, and I agreed. But I did have a copy of Fundamentals of Database Systems, recommended reading for PostgreSQL hackers [not people who write apps with PostgreSQL