Properties

In Freebase, a property is associated with a type. Put another way, a type is a collection of related properties.  

For example, the Person type includes properties such as:

• Birthplace
• Birth date
• Parents
• Country of Nationality

The Film type, as another example, includes properties such as:

• Initial release date
• Directed by
• Produced by
• Genres

Types are tied to topics. And the types that have been tied to a topic determine the properties that topic will have. A property itself is like a field in a form.

For example, the topic for Martin Scorsese is tied to the type Film director, which includes a property for Films directed. (You can add multiple instances of one property, as needed; so the Flims directed property could expand to cover all of his films.)

Freebase has an expected type associated with each property. That is, every property specifies what type of topic must appear in it. For instance, the Recording Artist type has a property Genre, which wants to be filled in with topics that are typed as Musical Genre.

For many properties, the appropriate value (i.e., the info you fill in) is actually a link to an existing topic in Freebase. For properties that can be filled in like this, when you start typing, you'll get a list of topics you can pick from (this feature is called autocomplete). For example, in the Martin Scorcese topic, if you were in the Films directed property and you started typing "The Dep", the system would give you a list that would include The Departed. Once you've picked it, the film title becomes a link between Martin Scorsese and the topic that represents the film The Departed.

One of the cool things about Freebase is that many properties link in both directions. In other words, if you're in the Martin Scorcese topic and you add The Departed to his Films directed property, The Departed's Director property will automatically fill in with Martin Scorsese.