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Knowledge graphs vs. vector databases: which is better for AI implementations?
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A minimalist depiction of stacked layers, where the top layer is a web of interconnected nodes (the knowledge graph) and the bottom layer is a smooth vector plane (the vector database). Thin, elegant lines link the layers, suggesting their interconnected roles in RAG. The art deco style will be sleek and refined, with soft colors and geometric balance.

Knowledge graphs vs. vector databases: which is better for AI implementations?

By Jacob Andra / Published September 30, 2024 
Last Updated: September 30, 2024

Knowledge graphs and vector databases are two very different architectures for knowledge management. Knowledge graphs excel at representing complex data relationships and enable nuanced queries. Vector databases efficiently handle unstructured data for fast similarity searches.

Main takeaways
Knowledge graphs excel at representing complex relationships between data points.
Vector databases enable faster similarity searches on large datasets.
Knowledge graphs are better for tasks requiring deep semantic understanding.
Vector databases handle unstructured data more efficiently than knowledge graphs.
The two architectures aren’t mutually exclusive and can be combined.

What is a knowledge graph?

A knowledge graph is a structured representation of data that connects entities (such as people, places, or concepts) and their relationships. It creates a web of interconnected information that reflects how different elements relate, much like how a mind map organizes knowledge.

How does a knowledge graph work?

Knowledge graphs rely on semantic relationships to model data. This means they use context, meaning, and relationships between entities to organize complex and diverse information.

For example, in a knowledge graph, a “company” entity might be linked to “employees,” “products,” and “competitors,” showing how all these elements interact. This way, the graph provides richer, more nuanced insights than traditional databases, which often store data in isolation.

Knowledge graph applications

Knowledge graphs are the preferred data solution for:

  • Search engines: Google uses a knowledge graph to enhance search results by understanding the complex relationships between concepts and delivering more relevant answers.
  • Recommendation systems: Platforms such as streaming services use knowledge graphs to suggest content by connecting user preferences with related items.
  • Data integration: Knowledge graphs can help businesses integrate diverse datasets by mapping relationships across many systems and sources.

What are the benefits of a knowledge graph?

  • Deep relationship-based insights: Knowledge graphs reveal connections that may not be immediately obvious. This can drive more informed decision-making.
  • Scalability: Knowledge graphs can grow alongside a business and accommodate larger, more intricate datasets.
  • Better search capabilities: By understanding intricate relationships between data points, knowledge graphs improve the accuracy of search results and support natural language queries.

What are the limitations of the knowledge graph?

  • Not optimized for unstructured data: While great for structured information, knowledge graphs struggle with unstructured data such as images or free-form text.
  • Increased complexity with scale: As more entities and relationships are added, managing and querying the graph can become more challenging and resource-intensive.
  • Suppressing emergent understanding: Because a knowledge graph spoon-feeds relationships, it doesn’t promote the sorts of emergent insights that generative AI is capable of. In short, the knowledge graph can function as a bottleneck.

What is a vector database?

A vector database is a system that stores and retrieves data in the form of vectors, which are numerical representations of information. Vectors are useful for representing unstructured data such as text, images, and audio, so vector databases are important for AI and machine learning applications that rely on similarity searches and pattern recognition.

How does a vector database work?

Vector databases use mathematical algorithms to represent data as vectors in a high-dimensional space. Each vector captures the essence of a piece of unstructured data, such as the meaning of a sentence or the visual features of an image.

When a query is made, the database compares the query vector to stored vectors and returns the most similar results based on proximity in the vector space. Vector databases enable fast, efficient retrieval of similar items, even across vast datasets.

Where are vector databases used the most?

Vector databases are most commonly used in applications involving:

  • Similarity search: Finding items that are "like" other items quickly and efficiently.
  • High-dimensional data processing: Handling complex data with many attributes.
  • Pattern recognition: Identifying trends or anomalies in large datasets.
  • Semantic analysis: Understanding the meaning and context of text or other data.

These capabilities make vector databases ideal for powering recommendation systems, natural language processing tools, image and video search engines, anomaly detection systems, and advanced search functionalities. They're particularly valuable in AI-driven applications where speed and accuracy in processing complex, unstructured data are crucial.

What are the benefits of a vector database?

  • Efficient handling of unstructured data: Vector databases process large amounts of unstructured information, such as text, images, or audio, by converting them into vectors and embedding those vectors in the high-dimensional vector space.
  • Speed and scalability: The ability to perform rapid similarity searches makes vector databases well-suited for AI-driven tasks where speed is crucial.
  • Support for machine learning: They seamlessly integrate with machine learning models to boost their ability to search, retrieve, and analyze unstructured data.
  • Supports emergent learning: Because of its sheer complexity, a high-dimensional vector database allows open-ended insights on the part of a generative AI system. This promotes emergent intelligence.

What are the limitations of a vector database?

  • Limited relational insights: Vector databases are great for unstructured data, but not so good for those instances where you’d want to create a defined relationship between elements.
  • Computational cost: Storing and searching through high-dimensional data requires significant computational power, which can drive up resource demands as the database grows.

Differences between knowledge graph and vector database

Art deco aesthetic with metallic, isometric grid blocks (knowledge graph) on the left, contrasted with vibrant, glowing undulating waves (vector database) on the right. Minimalist but with depth, sharp geometric structures versus smooth, dynamic forms. Futuristic, clean composition with subtle glowing effects.

Knowledge graphs and vector databases offer distinct approaches to data management, each suited for different types of information and use cases. Let's take a look at how they compare:

Knowledge graphVector database

Data representation

Entities and relationships

Mathematical vectors

Data type

Structured, relational data

Unstructured or semi-structured data (e.g., text, images)

Query type

Graph traversal and pattern matching

Similarity search based on vector distances

Strengths

Complex relationship queries and semantic understanding

Fast similarity matching and contextual similarity

Query mechanism

Semantic and relationship-based queries (e.g., SPARQL)

Similarity search using vector comparison

Scalability

Doesn’t scale as well

Scales efficiently with data volume and unstructured data

Use cases

Semantic search, data integration, knowledge representation

Retrieval augmented generation (RAG) AI applications, other LLM applications

Natural language processing

Supports semantic understanding

Focuses on contextual similarity and embeddings

Update flexibility

Easy to add new relationships

Requires recomputation of embeddings when data changes

Query speed

Varies with the complexity of relationships

Consistently fast for similarity-based searches

Storage

Can be storage-intensive due to relationship complexity

Typically more efficient for large-scale unstructured data

Best for

Relational context and interconnected data (e.g., search engines, ontology)

AI-driven searches, content recommendation, pattern recognition

How to choose the right architecture

Your choice between a knowledge graph and a vector database depends on your specific requirements and data characteristics.

Choose a knowledge graph if:

  • Your data has fewer relationships that are highly defined
  • You need to perform multi-hop queries
  • Semantic understanding is crucial for your application
  • Your system requires frequent updates to data relationships

Opt for a vector database when:

  • You work primarily with unstructured text or image data
  • Fast similarity searches are a priority
  • Your dataset is large and continuously growing
  • You need efficient scaling for high-volume data processing
  • You want to promote emergent learning rather than defined relationships

Consider a hybrid approach (blending the two architectures) if:

  • Your use case demands both relational queries and similarity searches
  • You have a mix of structured and unstructured data
  • You want to leverage the strengths of both systems for comprehensive information retrieval

Looking to the future

In the future, we expect generative AI capabilities to render knowledge graphs obsolete. Or, perhaps a better way of stating it: the knowledge graph functionality will be subsumed under the capabilities of AI.

As generative AI becomes increasingly intelligent, it will contain its own knowledge graph functionality. That is, even in the absence of an explicit knowledge graph, the AI will understand and be able to articulate all of the connections and relationships one would hope for from a knowledge graph—plus many more.

Reach out to Talbot West

If you’re considering an AI implementation, we’d be happy to discuss the best options. We can help you with a feasibility study, pilot project, and tool assessment. Schedule a free consultation, and check out our services page for the full scope of our offerings.

Work with Talbot West

Database FAQ

Knowledge graphs are still powerful tools in many industries. Their graph structure represents complex relationships, particularly in semantic search, recommendation systems, and fraud detection. Knowledge graphs provide a deeper understanding of interconnected data; they’re valuable for organizations dealing with complex, relational information.

The best vector database depends on the use case. Milvus and Pinecone are popular choices because of their ability to handle high-dimensional vector space and perform efficient similarity searches. Each database type offers strengths for AI-driven applications requiring fast, scalable performance.

A vector database is better than a knowledge graph for many types of complex queries that involve unstructured data or loose, implicit relationships. Graph databases are good for graph search, while vector databases perform well in multi-dimensional spaces with efficient similarity searches based on cosine similarity.

Vector databases have a crucial role in large language models (LLMs). They store and retrieve vast amounts of text embeddings for quick similarity searches. This capability supports tasks such as semantic search, recommendation systems, and question-answering. Vector databases provide the necessary infrastructure for efficient retrieval of relevant responses in applications powered by large language models.

A vector database is a type of database optimized for storing and querying high-dimensional vectors, often used in machine learning applications. RAG is a technique that combines information retrieval with text generation. RAG uses vector databases or other retrieval methods to fetch additional context for generating more accurate and informed responses to a user query.

Generative AI is being used in the automotive industry to drive innovation and efficiency across various domains. Here are some key ways it is being utilized:

  1. Design and prototyping: generative AI algorithms can create multiple design iterations quickly, optimizing for factors like aerodynamics, weight, and material usage. This accelerates the design process, allowing engineers to explore a wider range of possibilities and develop more efficient and innovative vehicle designs.
  2. Material innovation: AI aids in the research and discovery of new materials with desirable properties, such as increased strength, reduced weight, or better sustainability. Generative AI models simulate and predict the performance of these materials under different conditions, speeding up the development of advanced materials for automotive applications. 
  3. Manufacturing optimization: generative AI can design efficient production layouts and processes, optimizing the use of space, equipment, and resources. This leads to more streamlined manufacturing operations, reducing costs and increasing productivity.
  4. Personalized in-car experience: generative AI enhances the personalization of in-car experiences by analyzing user preferences and behaviors. It can generate custom configurations for infotainment systems, seating arrangements, and climate control settings.
  5. Autonomous vehicle training: generative AI is used to create diverse and complex driving scenarios for training autonomous vehicle systems. By simulating a wide range of conditions and potential hazards, these AI systems help improve the safety and robustness of self-driving technology.
  6. Enhanced safety features: generative AI can develop advanced safety features by analyzing vast amounts of data from real-world driving incidents. It helps design systems that predict and prevent accidents, improving overall vehicle safety.
  7. Customer service and sales: AI chatbots and virtual assistants, powered by generative AI, provide personalized customer service and sales support. These systems can answer queries, recommend products, and assist with the purchase process.

About the author

Jacob Andra is the founder of Talbot West and a co-founder of The Institute for Cognitive Hive AI, a not-for-profit organization dedicated to promoting Cognitive Hive AI (CHAI) as a superior architecture to monolithic AI models. Jacob serves on the board of 47G, a Utah-based public-private aerospace and defense consortium. He spends his time pushing the limits of what AI can accomplish, especially in high-stakes use cases. Jacob also writes and publishes extensively on the intersection of AI, enterprise, economics, and policy, covering topics such as explainability, responsible AI, gray zone warfare, and more.
Jacob Andra

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