Rel: A Declarative Language for Relational Data
Hayk Ghukasyan · 2025
Relational database systems remain the backbone of data management in modern enterprise applications. Although decades of research have refined SQL and relational algebra, developers frequently encounter issues involving verbosity, ambiguity in multi-nested queries, and integration with modern type systems. In this paper, we introduce Rel-a declarative programming language designed to unify relational algebra with strong typing, modularity, and concurrency. Rel features syntactic constructs that reduce boilerplate, easily compose across multiple relations, and leverage a sophisticated type system for safe query transformations. We showcase the key design principles of Rel, illustrate a selection of sample programs (including advanced join optimizations), and discuss performance benchmarks against conventional SQL. Finally, we explore the potential for broader adoption and outline directions for future research.