Let’s talk about relationships — nothing gossip-y — but, rather, how does one thing relate to something else? On Wikidata we talk about relationships using something called properties. Part of the semantic triple (subject, predicate, object — or in Wikidata parlance, item, property, value), properties define how one thing relates to another on Wikidata. Is it a date? A name? A location? An image? An identifier. Here’s an example: for those in the northern hemisphere, we may be thankful that this post is being published as spring (Q1312) follows (P155) winter (Q1311). In that sentence ‘follows’ is the property that explains a relationship between ‘winter’ and ‘spring.’ The Wikidata community uses properties to define any kind of relationship between things. How many properties are there? I’m glad you asked.
As of March 2022, there are around 10,000 properties on Wikidata. Roughly 7,000 of these are external identifier properties (external identifier properties correspond to external collections — museums and libraries — whose collection includes a person, place or concept that also exists in Wikidata). That leaves around 3,000 properties the community uses to describe everything. You can read the discussion page of any property to orient yourself to that property, but there are other ways to understand how properties work too. Knowing where to start with those can be a little overwhelming. This post will profile properties about properties. If that sounds confusing, I get it! I’ll provide plenty of examples to contextualize everything and help you better understand how properties work.
Let’s learn through examples. As you discover properties, wouldn’t it be wonderful if there were a way to see the property in action to know if you were using it correctly? I have good news for you: there IS a property that does this. It’s called Wikidata Property Example (P1855 for super-fans). Click that link, and read all about property examples, including links to queries where you can see thousands of properties — with examples — in the wild on Wikidata. To review: there is a property on Wikidata that exists to give you examples of properties and how they work. Can you focus the query on a specific property? Yes. Can you get multiple examples for one query? Yes. Does the example I shared list all properties with examples? Yes! Is this is one of the best ways you can use properties like a pro? Absolutely.
Now that you’re familiar with one way to learn how a properties works, consider this: maybe the dataset you are working with requires you to describe an inverse relationship — or something that is the opposite of something else. If only there were a property that could express an inverse relationship! Well, today is your lucky day because there is a property called inverse property (P1696) that does exactly that. Please note, and this is very important, that this property describes other properties on Wikidata and their relationship is inverse to each other. For example if what you’re describing follows something or if it is followed by something else, the follows (P1696) property would be connected by the inverse property. Another example would be family relationships like a parent property (mother/father) and the child property is the property for you!
If you’re not talking about relationships (properties), but rather items — concepts, people, places — there is a completely different property called opposite of (P461) that the community uses to describe conceptual opposites. What’s a conceptual opposite? You can think of this as the opposite of the color white is the color black. The opposite of summer is winter. It’s okay if it’s a little confusing. Examples will help distinguish these two. To review: an inverse property is used exclusively with relationships — child/parent, capital/capital of, officeholder/position held, owner of/owned by. Another property “opposite of” is used exclusively to describe opposing concepts. Both of these properties are great for distinguishing related things on Wikidata. Let’s move on to another distinguished property.
You are nearly a property pro. You’re feeling confident, you understand how these descriptive connections relate to each other. The world is your oyster and you want to describe more things with more properties, more accuracy, and more precision. I love the enthusiasm. There’s a property that can help you do this: it suggests related properties on Wikidata. It’s called — you guessed it — related property Property (P1659). You can use this property to see other properties related to the one you are wondering about. You can think of it as a “see also” recommendation for properties. There are MANY location-type properties on Wikidata. Suppose you want to know all of the properties related to P131, which describes where things are geographically located? You could use “related properties” in a query to get a list: just like this! You can think of this property as a way to reveal how properties are related to similar properties. Using this property will help make you a super-describer on Wikidata. There’s nothing you can’t describe now!
These three properties (well, four) should reveal more about how to describe anything on Wikidata. Learning how to use properties on Wikidata is essential for maintaining data quality and usefulness of the data. It is also one of the most effect ways to learn how to query and write better queries. The more familiar you are with properties, the more you will get out of Wikidata (and likely any other dataset you’re working with whether it’s part of Wikidata or not). Now that you know more about properties on Wikidata, consider these two things:
- Wikidata will always require new properties. If one is missing, you can propose it here. Properties also change over time. If an existing property isn’t working for you (or has never worked for you), you can propose changes on the property’s discussion page. The only way Wikidata will ever be an equitable resource is if property usage and definitions work for all kinds of data and relationships in the world.
- The properties I’ve shared with you in this post themselves are incomplete. The community could always use more examples, better definitions, and other ways of describing things. Adding statements to items and properties is a very important way you can help improve these resources.
Stay tuned for more Wikidata property exploration posts here. And if you want to learn more, take the Wikidata Institute course I teach!