Datonummerstandarder

Datonummerstandarder is a term used to describe standardized methods for encoding dates as numbers in data systems. The aim is to ensure consistent interpretation, comparison, and processing of dates across software, databases, and communication protocols, reducing locale- and format-related ambiguities. These standards cover both human-readable representations and numeric encodings, along with validation rules and interoperability guidelines.

A central pillar is ISO 8601, which defines calendar dates and times in a machine-friendly form. The most common representation is the year-month-day format, such as 2024-07-04, and a compact variant like 20240704. ISO 8601 also specifies week-based and ordinal date forms, for example 2024-W27-3 (the third day of the 27th week of 2024) and 2024-186 (the 186th day of 2024). RFC 3339 represents a profile of ISO 8601 tailored for Internet protocols, emphasizing timestamps with time zone information.

Other date-number encodings include ordinal dates (year plus day of year), Julian day numbers (the continuous count of days from a reference epoch used in astronomy), and Modified Julian Date (a shifted version of the Julian day count). In computing, Unix time (seconds since 1970-01-01 UTC) is widely used as a timestamp, though it is not a calendar date in isolation and requires conversion for human readability.

Implementation considerations for datonummerstandarder include handling time zones, leap years, and daylight saving effects; choosing formats that balance readability, storage efficiency, and arithmetic capability; and maintaining backward compatibility with legacy systems. The standards support data exchange, archival accuracy, and interoperability across international contexts.

See also: ISO 8601, RFC 3339, Julian day number, Modified Julian Date, Unix time.