Dave Wells Designing and Implementing Semantic Data Layers

Data has a meaning problem. Semantic data layers solve it. Semantics, applied to data, is the discipline of making meaning explicit, consistent, and durable. Semantic data layers are the architectural expression of that discipline. This book shows you how to build them. Data management has always been messy. Inconsistent metrics, brittle integrations, data silos, and confusing dashboards persist even after heavy investment in data lakes, warehouses, pipelines, BI tools, metadata catalogs, and modern platforms. At the core, these are not technology problems; they're problems of meaning. More infrastructure doesn't fix a meaning problem. It expands it. AI workloads add new urgency: systems that act autonomously on data they don't fully understand compound the cost of every inconsistency. Semantic data layers turn scattered data definitions into shared, stable, reusable business meaning that is independent of the physical structures that hold the data. The result is strong data interoperability, reliable analytics, improved self-service access, reduced technical debt, and a practical foundation for trustworthy AI. Building semantic layers well requires three things in the right order. First, architecture: understanding the five types of semantic layers (enterprise, domain, integration, enrichment, and consumption) and where each belongs in your data management world. Next comes design: ontology, taxonomy, semantic models, knowledge graphs, and property graphs. This is the conceptual work that captures how your business actually understands its data. Semantic models that business people can read and validate are more durable than technically precise models that only engineers can interpret. Then comes implementation: building semantic layers as software through APIs, data products, data contracts, data virtualization, and schema registries. Architecture first, next design, and then implementation. This book covers all three. Written for data architects, data engineers, data leaders, data governance professionals, analytics teams, and the emerging Semantic Layer Engineer, it is a practical guide to reducing data friction, improving data quality, increasing reuse, and enabling self-service analytics across a complex enterprise. When data has shared meaning, systems connect more easily, people trust the answers, and AI has the context it needs to reason responsibly.