betweenrelational

Betweenrelational is a term used in database theory to describe a family of data models and query techniques that extend the traditional relational paradigm to natively support range-based and interval data. It is not a standardized technology but rather a concept discussed in academic and experimental contexts to address expressiveness and performance for between-type constraints.

In a betweenrelational model, data are stored in tables similar to those in SQL, but with enhanced semantics for intervals. Columns may carry interval values or be associated with interval metadata, and relations can express not only equality-based joins but also containment, overlap, and adjacency between intervals. A typical between predicate captures statements such as a value or interval A lies between two bounds B and C, or that two intervals overlap.

Query processing in betweenrelational approaches often extends SQL with between-relational operators or functions. Evaluation relies on interval-aware indexing structures such as interval trees, segment trees, or spatial indexes, in combination with traditional B-trees or hash-based structures. Optimizers may perform interval-aware predicate pushdown, join reordering based on range selectivity, and caching strategies keyed by interval boundaries.

Use cases commonly cited include temporal databases, scheduling and resource allocation, versioned data, and geospatial or temporal analytics that require efficient handling of ranges and interval relationships. Limitations noted include lack of standardization, increased system complexity, and interoperability challenges with conventional relational systems. As a concept, betweenrelational guides research into integrating range semantics more deeply into relational workflows.