Index text files with tags and search

I've got a SQL Server database full of documents that I'd like to extract into text fi开发者_开发百科les and index according to particular tags in the docs and tags that I add.

Is there a tag-based text indexing API or library out there I can use? As a follow-up, I also need a client that can search these things.

I'm thinking about extracting the docs out as XML...

Have you looked into SQL Server Full Text to search text/varchar data?

Otherwise, you can use Indexing Services / Windows Search. The great thing about this option is that you can use custom, searchable meta tags.