The install script defined a new table. But how does Drupal know that this table is to be treated as part of a content type? In fact, how is Drupal to know that we are defining a content type at all?
Note
In the first chapter, we discussed nodes. From the developer's point of view, each piece of content is backed by a node and (perhaps) some extensions to that node. What extensions are used depends on the content type of that piece of content. The table we just created represents extensions to the node for our biography content type.
The hook function hook_node_info() is used to register a new content type. Other functions that we will look at shortly (namely, our implementation of hook_load()) will provide Drupal with information on how we have augmented the node with our custom fields.
An implementation of the hook_node_info() hook must return an array of information about the node. This information is basic, and does not include details about the table...