In order to make the most of the entity APIs integration with other modules, such as Views, we need to describe the properties of our entity in more detail. The API can infer some information about a property based on our schema but we need to tell it that the integer stored in the updated_at column is actually a timestamp. We will do this by implementing
hook_entity_property_info() and describing each of our entities properties. With these definitions in place you will be able to use the formatters in Views much like you would for individual fields on content types provided by core.
Note: Before you implement
hook_entity_property_info() the API makes an educated guess about each property but once you've defined a single property, the API expects you to define all of the properties for your entity. Use the
.install file in your module to get a complete list of the properties you need to define with
hook_property_entity_info. You can also define additional properties that aren't mapped to fields in the database (these can be used for static properties).