How do I create a simple site search?

[eluser]LuckyFella73[/eluser]
I think the hardest part with this is to create a good database structure.
All the pages the user may found in a result list have to be stored in db
and you have to build a system where you can link to the pages from result list.

If you are just searching in a area of the site - for example you have a news list
and get the detail view when clicking at a row then a search function is quite
easy. But when you want to search through the whole site and it have to be
possible to find every page that exists then it gets a bit harder ..