Drupal module write to database using FAPI

Does anyone know of a tutorial that shows creating a form and writing that data to a databa开发者_如何学JAVAse? This is what I am trying to accomplish or can anyone put together the simple code so that I can understand how it works?

I would start with Drupal's API doc on Forms. Also, check out Drupal's documentation on their Database Abstraction Layer.