SPARQL queries of the Billboard Hot 100

Current and historical data!

Wikipedia describes the Billboard Hot 100 as “the music industry standard record chart in the United States for songs, published weekly by Billboard magazine. Chart rankings are based on sales (physical and digital), online streaming, and radio airplay in the U.S.” A song that ranks highly there is a hit song (in the U.S.) by definition. The data goes back to the beginning of the chart’s history in 1958, when Rick Nelson’s Poor Little Fool was the number one song.

Visualizing RDF

I see nodes and edges...

I recently did a review of options for creating visual representations of RDF data. I didn’t just want a general visualization tool, but something that understood RDF enough to represent class instances and literal values differently. I will emphasize instances because several tools out there can read RDF schema or ontologies and create a visualization of classes and their relationships and potential properties, but I want to see instances with their property values.

I’ve understood SPARQL’s property path features well enough to demo them in the “Searching Further in the Data” section of my book Learning SPARQL. (See example files ex074 - ex085.) To be honest, I have very rarely used them in actual queries that I’ve written. I’ve only just realized how the property path slash operator can help with a pattern that I have used in a large percentage of my queries. It makes these queries more concise and removes at least one…

Triples about existing triples

The easy way and the hard way.

Several years ago in the blog post RDF* and SPARQL* I described how I had played with implementations of the new reification syntax that Olaf Hartig and Bryan Thompson proposed in their paper Foundations of an Alternative Approach to Reification in RDF. I found the new syntax to be straightforward and useful. As you can see from the recent W3C Community Group Report RDF-star and SPARQL-star, this syntax has progressed—with a more search-engine-friendly spelling of the spec’s name—closer to…

Querying for labels

The normal way and the wikibase:label service way

In my last blog entry I discussed various ways that different RDF datasets assign human-readable labels to resources, with the rdfs:label property being at the center of them all. I mentioned how doesn’t use rdfs:label but its own equivalent of that, schema:name, which its schema declares as a subproperty of rdfs:label. Since I wrote that, Fan Li pointed out that Facebook’s Open Graph protocol also has their own equivalent: og:title, which you can see used in the HTML…

Human-readable names in RDF

Sometimes simple, sometimes not.

First, reviewing some basics before I discuss the edge cases: resources in RDF are represented by URIs, and the spelling of a given URI often provides no clues about what the URI represents. For example, you wouldn’t know from looking at that it represents “dog” as a Wikipedia topic. (We’ll see below that this is a for a good reason.)