Data Virtualization platforms provide a unified semantic query layer that federates data across warehouses, lakes, operational databases, and SaaS sources — enabling real-time access without physically replicating the data into a central store. Core capabilities include cross-source query federation with pushdown optimization, source abstraction and schema unification, intelligent caching and materialization, governance enforcement consistently across connected sources, and a logical data model that insulates consumers from physical-storage changes. The category serves as the 'query fabric' for organizations with regulatory, latency, or acquisition-era constraints that prevent physical consolidation. Leading vendors include Denodo, Starburst, Dremio, TIBCO Data Virtualization, and Trino (open source).