Semantic Layers

Concepts: dmSemanticLayer

Define Metrics Once, Use Everywhere A semantic layer is a logical layer that defines business metrics in one place and makes them available to every consumer: dashboards, notebooks, APIs, and ad-hoc queries. Without one, every team defines 'revenue' slightly differently. Marketing counts refunds. Sales does not. Finance uses a different exchange rate. The numbers never match. The semantic layer sits between the physical tables and the consumers. It defines: what 'revenue' means (SUM(amount) WHERE status != 'refunded'), what dimensions are valid for grouping, and what filters are available. Every consumer uses the same definitions. Tools and Approaches The semantic layer solves the 'which number is right?' problem. When the CEO asks for revenue and gets three different answers from three te