One of our readers points out a set of interesting database models. For example #90 is for Science and Research applications and handles various Meta Data fields, and #94 is a template for searching Newspaper Articles.
The main list of database models is at:
http://www.databaseanswers.org/data_models/
We're not gonna take sides on this, but this is an online Webinar that compares the two leading open source databases.
Two minor warnings: 1: Registration required, and 2: it's from a company that offers a commercial version of PostgreSQL, so keep that in mind.
This guy's website is pretty interesting too.
http://www.erikhallander.com/blog/2008/free-stuff-automatic-mysql-table-optimizer.html
This looks like a really nice tool for database administrators.
Although this download is free, their site has a lot of other cool stuff (not free) for ETL ("Extract, Transform, Load") and database conversion tools.
http://www.dbsoftlab.com/index.php/Freeware/Database-Browser.html
