nrowobject

nrowobject is a lightweight data type used in data processing frameworks to encapsulate the concept of a dataset's row count. It emphasizes a single numeric quantity while possibly carrying metadata about how the count was obtained, such as whether it is exact or estimated.

Design and representation: An nrowobject typically stores an integer count and may include flags for estimation, precision, or bounds. It is often immutable and comparable, allowing arithmetic and ordering operations with standard integers or other nrowobjects. In many implementations, there are convenience methods such as toInt(), isEstimated(), and fitsIn(int).

Usage: nrowobject is passed between components to report results, validate input sizes, or drive sampling and paging logic. For example, a data reader might return an nrowobject representing the number of rows, while a transformer may accumulate counts from multiple sources by producing a new nrowobject via addition.

Implementation notes: Because row counts can be large, implementations use 64-bit integers in most environments. If a count is derived from a query, an nrowobject may carry estimation status or upper/lower bounds to support early optimizations. Serialization formats often preserve the count and metadata for distributed processing.

See also: row count, cardinality, data schema, metadata in data processing, lazy evaluation.