calendardaylike

Calendardaylike is a conceptual term used in data modeling and software design to describe values that represent a specific calendar day with no inherent time-of-day component. A calendardaylike value encodes the civil date (year, month, day) according to a calendar system—typically the Gregorian calendar—and supports day-level operations such as comparison, addition or subtraction of days, and formatting, but not time-based arithmetic.

In practice, calendardaylike values are stored as date-only representations, such as ISO 8601 strings like YYYY-MM-DD or compact forms like YYYYMMDD. They are used in contexts where time-of-day is irrelevant or should be neutralized, such as daily aggregations, scheduling by date, or date-based indexing. They differ from timestamp or datetime values that include hours, minutes, seconds, and possibly time zone information. Many libraries offer date-only types that qualify as calendardaylike, providing operators for ordering, range queries, and normalization.

Key considerations when working with calendardaylike data include handling time zones for display and comparison, clarifying which calendar system is in use, and accounting for leap years and month lengths. In some ecosystems, alternate calendar systems may require specific handling or conversions.

Common applications span calendar apps, billing cycles, daily reports, event planning, and data warehouses designed for daily granularity. The term calendardaylike is not universally standardized, and its exact definition can vary by language or framework, though the core idea remains a date without time. See also: date, date-time, ISO 8601, temporal data type, calendar.