Simple database question: tags

[David Bovill]

Going to have a go at knocking up a database for RevCode handlers - and I
want to create a database schema for it. I know I want del.icio.us style
tagging, and I'll be indexing them with the language terms used as well as
keywords such as "html", "array", "outline" or "view" etc I'm thinking I
need a database as I know I'll want to experiment a lot with searches -
particularly for handlers with the highest hits... and that seems a bit
hairy to do with arrays and memory based indexes?

So the question is - is there a resource anyone knows of for database
schema's - a sort of design pattern thing for databases for people like me
that know a little but not enough to design one except by trial and error?
Say for folksonomy tagging for a starter?