You can cache--or store--sources of dynamic content in a Design Note. This lets you work on a site even if you dont have access to the database or application server storing the sources of dynamic content. Caching may also speed up development by eliminating repeated access across a network to the database and application server.
If you make changes to one of the content sources, you can refresh the cache by clicking the Refresh button (the circle-arrow icon) in the top right corner of the Bindings panel. (Expand the panel if you dont see the button.)