Querying a Knowledge Graph — SPARQL and Graph Patterns
A knowledge graph you can't query is just a diagram. The power of the graph is realized when you can ask it questions — and querying a graph is fundamentally different from querying tables. Instead of joining rows, you describe a pattern of connections and ask the graph to find every place that pattern occurs. This post covers SPARQL, the standard query language for RDF graphs, and the graph-pattern-matching mindset that makes graph queries so expressive for connected questions.
Querying a graph is pattern matching, not joining: you describe a shape of nodes and edges and the engine finds every match. SPARQL (and Cypher for property graphs), path expressions for arbitrary-depth connection that SQL can't express, and inference-aware queries over the reasoned graph.