beginDate

BeginDate is a term used across data modeling, software applications, and user interfaces to denote the starting point of a time interval. It typically marks the earliest date included in a range, such as the beginning of a contract, a project phase, a report period, or a data query window.

In practice, beginDate is usually stored as a date or timestamp. Common representations include ISO 8601 dates (for example, 2025-07-01) or full timestamps with time zones (for example, 2025-07-01T09:00:00Z). Some systems use integers representing epoch milliseconds or seconds. When time zones matter, beginDate may be recorded in a specific zone or in UTC, with conversions performed as needed.

BeginDate often appears alongside an endDate or duration to define a complete interval. In databases, APIs, and reporting tools, it is used to filter results, schedule events, or calculate period-based metrics. Semantics can vary: some systems treat beginDate as inclusive (the period starts on that day), while others may treat it as exclusive or ambiguous unless explicitly defined.

Validation and consistency considerations include ensuring beginDate is not after the corresponding endDate (when present), handling null values appropriately, and validating format and time zone. BeginDate is frequently renamed in different contexts (for example, as startDate), but the underlying concept remains the definition of the interval’s commencement point.