Release Day: Get Started with Field API
Robust content modeling is made possible in Drupal 7 through fields. Attaching the right field types to entities makes it possible to bend your Drupal site to your will and scale it according to your needs. There are a lot of field types and field formatters provided in Contrib that you can download and install as modules to extend your Drupal 7 site. But what if you want to collect, store and format data in a particular way not provided by core or contributed modules? By providing custom fields and formatters through a module, you can control how your data is stored as well as provide one or more ways for the data to be output—through field formatters.