Linked Data, Ontology, and Knowledge Graph Explainer

Knowledge Graphs & Linked Data**

This document will help you understand why Knowledge Graphs, Ontologies and Linked Data are powerful tools for digital transformation, by demonstrating how the magic of Hyperlinks extends beyond the World Wide Web.


Understanding the essence of a graph.

Data-Driven Enterprise Transformation

How enterprises are looking to data-driven digital transformation to drive agility.

Linked Data

What is it?

A principled approach to structured data representation that manifests as a Web of Data.

Why is it Important?

It enables transparent access to data, courtesy of the power hyperlinks thereby enabling the following:

  • Integration of data across disparate data silos
  • Platform independent data connectivity across new and existing enterprise solutions

How is it created and used?

By adhering to the following principles:

  1. Name anything of interest unambiguously using a hyperlink (specifically, preferably HTTP URI due to HTTP’s ubiquity)
  2. Describe everything of interest using structured sentences where the subject and predicate are named using a hyperlink while the object is named using either a hyperlink or literal (which may be typed or untyped)

Using sentences (just like in the real-world) to describe anything of interest manifests as a powerful Web comprising data, information, and knowledge that’s rife with new insights that are discovered serendipitously.


What are they?

A collection of Entity Type and Entity Relationship Type definitions associated with a realm of discourse.
Ontologies are loosely-coupled and shareable, if constructed using Linked Data Principles.

Why are they important?

They provide a description of Entity and Entity Relationship Types that inform reasoning and inference performed by both humans and machines.

How are they created?

  • Name Entity Types & Relationship Types using a Hyperlink
  • Describe Entity Types and Relationship Types (Categories or Classes) using structured sentences deployed using Linked Data principles

Knowledge Graphs

What are they?

A collection of Entities, Entity Types, and Entity Relationship Types that manifests as an intelligible Web of Data informed by an Ontology

Why are they important?

They provide powerful foundation for creating a System-Of-Intelligence derived from existing Systems-Of-Record and Systems-Of-Engagement.

How are they created?

By describing entity and entity relationship types using sentences that are deployed using Linked Data principles. This approach is both flexible and progressive in that your Knowledge Graph is an evolving projection of enterprise reflection and potential agility .


Two examples of Knowledge Graphs launched from an HTML document. Hyperlinks in these documents take you into the massive LOD Cloud Knowledge Graph.

Use-cases and Demos

Progressive Knowledge Graph Construction Demo

This video showcases progressive enhancement of a Knowledge Graph via interactions akin to browsing and bookmarking, courtesy of our URIBurner Service (a live Virtuoso Instance with the Linked Data Transformation Middleware Module enabled).

Structured Data Sniffer & Sponger Middleware Demo

This video demonstrates how document viewing is enhanced via LOD Cloud Knowledge Graph look-ups performed by our Structured Data Sniffer Browser Extension (for Chrome and other Web Extensions compliant Browsers and Firefox).

Accessing COVID-19 Knowledge Graph from Excel Demo

Transparent access to the LOD Cloud Knowledge Graph using Microsoft Excel, courtesy of our SPASQL Query Language which enables transparent fusion of both the SQL and SPARQL Query Languages.

Accessing COVID-19 Knowledge Graph using SPASQL Demo

Another SPASQL demonstration, but this time via an HTML5-based Interactive SQL and SPARQL Query tool.

Accessing COVID-19 Knowledge Graph using Google Spreadsheet Demo

How SPARQL’s natural integration with the HTTP protocol enables powerful Data Access, Transformation, and Integration. In this case, the attached video demonstrates a SPARQL Query Results link that returns data in CSV format for natural consumption by a Google Spreadsheet instance.

Generating a Knowledge Graph from the Northwind SQL RDBMS using the Virtuoso RDF Views Wizard

This video demonstrates how a Knowledge Graph is derived in virtual form by transforming data associated with Tables attached to Virtuoso via ODBC. The end product is a navigable Knowledge Graph comprising Linked Data derived from the Northwind Database.