uqql

UQQL, short for Universal Query and Knowledge Language, is a hypothetical open-standard query language designed to provide interoperable access across heterogeneous data stores. It aims to unify querying over relational databases, graph databases, document stores, and knowledge graphs by offering a declarative syntax and consistent semantics.

Designed for federated data access, UQQL emphasizes readability, expressive power, and security. It proposes a modular architecture with a core query algebra and pluggable adapters that translate UQQL queries into engine-specific plans for SQL, graph query engines, or document stores. The language supports pattern-based matching, variable binding, complex filters, aggregation, and ordering. It also includes constructs for path expressions, optional patterns, and provenance tracking, enabling queries that traverse relationships while preserving data lineage.

Core concepts include a graph-oriented data model with nodes, edges, labels or types, and attributes. Queries are built from patterns that bind variables to data elements and can be combined with operators for selection, projection, and grouping. UQQL envisions cost-based optimization and role-based access control to ensure secure, scalable execution across stores.

Example (illustrative): MATCH (p:Person)-[:LIVES_WITH]->(home) WHERE home.city = 'Paris' RETURN p.name, home.street LIMIT 10.

History and status: UQQL has appeared in speculative or research discussions as a proposed standard for cross-store querying. There is no single official specification widely adopted, and practical implementations remain experimental or prototype-based. Related languages include SQL, SPARQL, and GraphQL.