ISO 8601

ISO 8601 is an international standard of ISO, which contains recommendations on numerical date formats and time. The title of the standard, Data elements and interchange formats - Information interchange - Representation of dates and times, Germanized "Data elements and interchange formats; Exchange of information; Representation of dates and times ".

With the acquisition in the European Standard EN 28601:1992, the recommendations of ISO 8601 on the date and times were - if they are purely numeric, thus in particular no full or abbreviated month names contain - according to ISO 8601:1988 in Germany, Austria and Switzerland. In September 2006, DIN ISO 8601 sparked these standards as well as the older DIN 1355 and DIN 1355-1 from the area of ​​the German standard work. In addition, the standard has been incorporated ( writing and design rules for text processing ) in the DIN 5008.

The numeric date format YYYY- MM-DD is often referred to as " international date format ".

  • 2.6.1 Proleptischer Gregorian calendar

Summary

The standard recommends a uniform notation of the date ( YYYY- MM -DD) and time (hh: mm: ss). An example of the date is 2004-06-14 (June 14, 2004) and for the time 23:34:30 (23 clock, 34 minutes and 30 seconds), and for both together 2004-06 - 14T23: 34:30. The order from the highest to the smallest unit is called in this context as " falling letters ".

The use of these formats is recommended especially in the field of natural sciences, software development, documentation and for international correspondence, since the greatest potential for error exists by country-specific formats.

In addition, the date format according to DIN EN 28601 has been filed in Germany on 1 May 1996 for single -standard numeric date format (eg 1996-05-01 ) and thus replaces temporarily the traditional format according to DIN 1355-1 (May 1 1996) from. All facilities that are within the control of DIN standards ( as well as all educational institutions and public institutions) were kept for the use of the new format. However, related large parts of the population in everyday life continue to the old format, which resulted in the revision of DIN 5008 in 2001 to re-approve the usual format, if so no misunderstandings arise.

The order of the points corresponds to the " natural" weights of numbers in number notation positional notation in mathematics, as the bigger units are facing the smaller ( year month, etc.). The format can be expanded on both sides with no breaks in the system to represent larger or smaller numbers. Besides facilitating information in this format, the search and sorting.

As a negative example, here are several country-specific notations for 2 April 2008 ( 2008-04-02 ) called: 4/2/08, 2/4/08, 08/4/2, 4/2/2008.

In addition, the standard defines as its predecessors since the 1970s, the Monday as the first day of the calendar week. The first calendar week of the year the week is defined by the first of January to Thursday. This always falls January 4 in the first calendar week. The basis is the Gregorian calendar, also in relation to the period prior to 1582 ( proleptic ).

Representation

Here variables used to always possibly with leading zeros:

  • J: year ( can be negative or zero) YYYY (can be extended, by convention )
  • JJ (with implicit century)
  • MM: 01 ... 12
  • Ww: week of the year 01 ... 53
  • T: Day of week 1 ... 7 (0 ≜ 7)
  • DD: day of the month 01 ... 31
  • TTT: day of the year 001 ... 366
  • Hh: 00 ... 23 (00 ≜ 24, 24 in 24:00:00 as the end time )
  • Mm: 00 ... 59 (00 ≜ 60)
  • Ss: 00 ... 59 (00 ≜ 60, 60 as a leap second)

Symbols used

Isolator with fixed dates

Separator when specifying time periods

Date

The month-day format was codified in ISO 2014 ISO 8601:1988, the week - day format including week count in ISO 2015 and the tag format in ISO 2711.

Daytime

Time zones

According to recommendation the difference to the Coordinated Universal Time (UTC ) must be specified by a contiguous date and time. The format is " ± hh: mm" or " hh ± " and thus takes into account both the time zone and daylight saving time. As a special value also, Z ' for UTC ( 00:00 ) can be entered. Needs to determine the local time information from a time in flight value for a ' ' subtracts the, according to one - ' are added.

Periods

A period of time is represented in the format [ start date ] P [ JY ] [ MM] [ WW ] [ TD ] [ T [ hH ] [ mM ] [s [. F] S] ]. The P shows as cited by Direction Information Letter, that a period of time (English periodical ) follows. Periods that contain a time portion will be defined as in the specification of the initial time point by a t. Therefore, the details of the months and minutes (M) can be distinguished. For the formatting of the initial time point, the same rules as for the normal dates apply.

Alternatively, if possible, start and end dates separated by a slash ( / ) must be specified. The standard also allows the use of two hyphens (-) in place of the slash.

  • 2005-08 - 09T18: 31:42 P3Y6M4DT12H30M17S: determines a time period of 3 years, 6 months, 4 days, 12 hours, 30 minutes and 17 seconds from 9 August 2005 ", shortly after half past six in the evening ."
  • P3Y6M4DT12H30M17S: the same time as the first example, but without defining a specific start date
  • P1D: "See you tomorrow at the present time. "
  • PT24H: " Until 24 hours from now. ", Which differs from the previous example in the case of a time change
  • 2005-08 - 09P14W: " The 14 weeks starting on 9 August 2005. "
  • 2005-08-09/2005-08-30: " From 9 to August 30, 2005 "
  • 2005-08-09 - 2005-08-30: " From 9 to August 30, 2005 "
  • 2005-08-09/30: "From 9 to 30 August 2005. "

Scope of the annual figures

The standard allows only the year from 1583 (the year after the introduction of the Gregorian calendar ) to 9999 without further agreement. Both the use of the years 0000-1582 as well as the dimension of the presentation format, with a greater range of years representable numbers is, reciprocal arrangements for data exchange partners are required. In cases of extensive presentation is to provide a sign, even the positive, absolutely necessary, the number of additional numerical points, even zero is possible to agree. For example, at present agreed two additional posts April 12, 1985 in expanded format as 001985-04-12.

The interpretation of data prior to October 15, 1582 is not fixed, it is therefore only dependent on the agreement reached. Another possibility here is in particular the application of the usual Julian calendar, but the standard also provides for the proleptic Gregorian calendar before.

Proleptischer Gregorian calendar

ISO 8601 provides for the possibility to use the Gregorian calendar for the period prior to its launch on 15 October 1582 but only at an appropriate agreement between the parties to the exchange. In this proleptic Gregorian calendar exists in contrast to the Julian calendar (see year zero), the year with the designation " 0000", which is a leap year. In an extended representation ISO 8601 in this case " -0001 " to the Julian year 2 BC, etc.

Technical standard Calendar era
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