Knowledge Graphs in AI: A Developer’s Guide to Structure, Scale, and Use

A developer-focused guide to understanding and using knowledge graphs for GraphRAG, LLM integration, schema design, and high-precision retrieval in 2025.
What are knowledge graphs

What is a knowledge graph?

A knowledge graph (KG) is a graph-structured data model that represents entities and the relationships between them. Unlike other databases that treat data as rows and columns, a KG links entities (nodes) using typed relationships (edges) to model domain-specific or general-purpose knowledge.

The term gained popularity with Google’s 2012 announcement of its own Knowledge Graph, but the approach has roots in earlier fields such as knowledge representation, ontologies, and the semantic web

Why Developers Use Knowledge Graphs

Knowledge graphs support:

  • Contextual enrichment of unstructured and semi-structured data.

  • Data integration across systems by connecting disparate identifiers.

  • Explainability in AI systems by surfacing connections and reasoning steps.

  • Efficient retrieval using graph traversal and subgraph matching.

In practical AI and data science pipelines, KGs are used to reduce the dependency on labeled datasets, improve transfer learning outcomes, and provide context to machine learning models.

“Combining symbolic and sub-symbolic approaches is the only scalable way to create explainable, adaptive AI systems.” — Dr. Pedro Domingos, Professor, University of Washington

What Makes a Graph a Knowledge Graph?

A graph becomes a knowledge graph when it meets three conditions:

Graph-structured

Nodes represent entities; edges represent relationships.

Semantic schema

Ontologies define types, attributes, and rules.

Mutable and evolving

New facts, entities, and schemas can be added continuously.

This trifecta makes knowledge graphs highly adaptive and suitable for both static knowledge representation and real-time reasoning.

Building and Maintaining Knowledge Graphs

Constructing a production-grade knowledge graph typically involves:

  1. Schema definition: Ontologies define the entity types, properties, and relationships.

  2. Ingestion pipelines: Natural Language Processing (NLP) and Extract-Transform-Load (ETL) systems pull data from structured (SQL, CSV) and unstructured (HTML, PDFs, logs) sources.

  3. Entity resolution and linking: Systems resolve duplicates and link entities across datasets.

  4. Quality control: Confidence scores, provenance tracking, and human validation loops.

  5. Reasoning and inferencing: Rule-based or statistical methods infer new facts.

Knowledge Graphs in Human-AI Interaction

In human-facing applications—search, chatbots, explainable AI—KGs support:

  • Structured explanations from graph traversal paths.

  • Entity disambiguation in user queries.

  • Real-time linking of information during conversations.

For example, a financial assistant bot can use a KG to:

  • Link a user query about “market volatility” to news, portfolio impact, and historical data.

  • Surface related topics like “interest rate changes” or “inflation risk.”

Developer Tooling and Frameworks

  • FalkorDB – High-performance graph database optimized for retrieval tasks (docs)

  • LangChainLLM orchestration framework

  • SPARQL / Cypher – Query languages for RDF and property graphs

  • RDFLib / pySHACL – Python libraries for RDF data validation

What is a knowledge graph in software architecture?

A knowledge graph models entities and relationships to integrate data and provide explainable AI reasoning.

How do knowledge graphs improve LLM performance?

They add structured context, reducing hallucination and improving relevance in Retrieval-Augmented Generation.

What tools are used to build a knowledge graph?

FalkorDB, LangChain, Cypher, and Python libraries like RDFLib and pySHACL are commonly used.

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Avi Tel-Or

CTO at Intel Ignite Tel-Aviv

I enjoy using FalkorDB in the GraphRAG solution I'm working on.

As a developer, using graphs also gives me better visibility into what the algorithm does, when it fails, and how it could be improved. Doing that with similarity scoring is much less intuitive.

Dec 2, 2024

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