singlerange

Singlerange is a term used in software design and data modeling to describe a constraint on a variable or field that restricts its value to a single contiguous range. In practical terms, a singlerange constraint limits values to an interval, typically expressed as [a, b], where a and b are bounds. For real-valued domains, a <= v <= b; for integer domains, v must be an integer within that interval. Some discussions distinguish closed, open, and half-open variants.

Examples include an age constraint of 0 to 120 or a progress field limited to 0 to 100. In both cases, any value outside the specified interval is considered invalid.

Implementation and constraints: Singlerange can be enforced with simple conditional checks or by using bounded types in a programming language. Example in pseudocode: if x < a or x > b then reject; otherwise accept. Databases and form validation often rely on such range checks to ensure data integrity.

Applications: Singlerange constraints are used in input validation, form handling, database schema definitions, configuration parameters, and user interface controls where a single, contiguous set of acceptable values is desired.

Variants and limitations: Variants include open or closed bounds, and lower-bound-only or upper-bound-only constraints. It is typically suited to numeric or ordinal domains. Limitations include the inability to represent multiple disjoint ranges (e.g., [0,10] ∪ [20,30]); for complex constraints, more expressive constraint systems are needed.

See also: Range, Interval, Bounded type, Constraint programming.