Interactive Knowledge Graph
Explore how entities are connected. Drag nodes to rearrange, click to see details.
Chapter 2: Interactive Learning Companion
Click each concept to learn more about its role in the Web of Data.
Directed labelled graphs
Graph patterns
Vocabularies & meaning
Data validation
External connections
What: Data in the Web of Data is represented as directed labelled graphs, consisting of nodes (resources or literal values) connected by edges (properties/relationships).
Why: Graphs are flexible (no fixed schema), natural for representing relationships, and easy to merge from different sources.
Example: ex:PecanPie --ex:ingredient--> ex:Pecans
What: Queries are patterns with variables that match against the data graph. SPARQL is the standard query language.
Why: Enables finding specific information by describing what you're looking for rather than where it's stored.
Example: SELECT ?recipe WHERE { ?recipe ex:ingredient ex:Pecans }
What: Shared vocabularies that define the meaning of terms. Includes class hierarchies (subClassOf) and enables inference.
Why: Allows machines to understand that different terms mean the same thing, and to derive new facts automatically.
Example: If Pecan is a TreeNut, and TreeNut subClassOf Allergen, then Pecan is an Allergen!
What: Shape definitions (like SHACL) that describe the expected structure of data.
Why: Ensures data quality by catching missing data, invalid values, and inconsistencies.
Example: "Every Recipe must have exactly one title and a positive duration"
What: Using URIs to link to external data sources, enabling dereferencing (following links) and identity links (owl:sameAs).
Why: Connects local data to the global Web of Data, enabling richer information.
Example: ex:Pecans owl:sameAs dbpedia:Pecan
Explore how entities are connected. Drag nodes to rearrange, click to see details.
Build RDF triples interactively. Every statement is a Subject → Predicate → Object triple.
Click on classes to see how inference works. If X is a subclass of Y, then all instances of X are also instances of Y.
Check your understanding of Chapter 2 concepts!
Impressive numbers showing the scale of the Web of Data today.