Magento query caching

How to cache the query result in magento if I am creating some module.

Basically I am creating one module for the announcement in which admin will add some announcement from the admin and it will be开发者_开发知识库 displayed on the front end(live website)

Now if the information entered though the admin is not dynamic so I want to cache the information while modifying(add, edit delete ) and show in front end. it will save my database query time

If you only cache the query result your block is still going to be generated every time. (Besides, MySQL already has a query cache)

It is better to cache the block output which saves even more effort for the server.
http://www.magentocommerce.com/wiki/5_-_modules_and_development/block_cache_and_html_ouput