How to write queries, import data, and visualise Knowledge Graphs with the RDFox

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Hello, and welcome to another episode of the RDFox introductory series.

In this episode, we're going to be showing you the RDFox console, our web UI where you can query and explore your data. Alongside this, we'll also be showing you how to create a data store and import some content.

So the first thing we're going to have to do is to start the endpoint. We can do this from a terminal that is already running RDFox. You can see here that I've started RDFox in sandbox mode, but if you're not sure how to do this already, check out one of our previous episodes that explains this in detail.

I'm going to run the command endpoint start, and we should see the output message: The REST endpoint was successfully started at the port number 12110. This is the default port number, but you can change this in your settings if you so choose.

From there, we can leave the terminal behind and head to a browser of our choosing, where we can go to the web address:  

http://localhost:12110/console/

From here, we'll be asked to create a new data store because none yet exists.

Before we do that, let's have a little walk around our UI.

On the left you can see some helpful information, first about RDFox, the version that we're running, and the data stores, if any exist, and finally, the documentation at the bottom.

Here you can also see some login information, either who you're logged in as or the option to log out. At the moment, because I'm using sandbox mode, I'm just viewing as guest, but of course you can set up further accounts should you wish.

Let's go ahead and create a new datastore. I'm following along with the workshop material, and if you are too, you'll need to call your datastore F1 with a lowercase ‘f’ and a numerical ‘1’, but if you're doing this for your own projects, you can call this whatever you want. From there, I can click Create Datastore and I'll be asked to import some content, but again, let's dismiss this and have a look around the UI.

First and foremost, you'll see the query editor front and centre. This is where we can write and edit our SPARQL that we’ll ultimately run to query our database. We can run it by clicking the ‘Run SPARQL’ button and we'll see any results that it creates in the table below.

We can also view and manage our prefixes here, but we'll come on to prefixes in a later episode. So again, check out those later episodes if that's something you'd like to know in more detail.

On the top bar, we can see some destructive commands like deleting content, clearing all content, or deleting the data store. We have an option to manage those prefixes I was talking about and import some content or create a new data store.

You'll also see there are additional tabs alongside our SPARQL editor. The Explore tab enables you to explore your results visualised as a graph, and the Explain tab allows you to explain reasoned results. To understand more about reasoning, check out a later video again to understand how we add results and enrich our data store with axioms and rules.

So let's go ahead and add some content with the ‘Add Content’ button. We'll be asked to choose a file, and we can simply select any total file of our choosing. I'm going to follow along with the workshop and add this up to 2020.ttl file. We'll need to make sure that this is in fact the file that we're after, and we'll be asked whether or not we want to update the prefixes with this file. In this case, we do, and all this will do will bring any prefixes defined in our file into the datastore with the rest of the data. From there, we can click ‘Add Content’, and in about a second, the four and a half million facts in this file will be added to our store. We can click finished and we're ready to go.

So we let's run this SPARQL query just to check out our results, and we can see a table of them below. If you'd like to understand how to write more complex, more functional SPARQL queries, check out the videos to come, where we'll go into several different kinds of queries and what's special about each of them.

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