Date format

from Wikipedia, the free encyclopedia
Date formats used worldwide:
  • year month day
  • Year month day and day month year
  • day month Year
  • Day month year and month day year
  • Month day year
  • Year month day, day month year and month day year

    • A date format is the form in which a calendar date is represented in writing. The date format determines

    • The order in which the components of the calendar date (the year , the month , the day ) are named
    • whether, and if so, which separators are inserted between the components of the calendar date.

    background

    Very different variants have been established around the world to represent the date, some of which are incompatible with one another. This can be seen in the fact that the same information in different representations can represent a different date.

    For example, the date 01/02/03 can be interpreted as:

    • 1 February 2003 ( 01.02.2003 the basis of the still common in German-speaking order according to DIN 1355-1 )
    • January 2, 2003 ( January 2, 2003 using the middle-endian order of the US format)
    • February 3, 2001 ( 2001-02-03 based on the sequence according to ISO 8601 / DIN 5008 )

    The interpretation of a date in this form therefore differs from country to country, i.e. it depends on the context and is therefore unsuitable for a globally uniform and reversibly unique representation.

    This fact was worsened by the turn of the millennium. Dates before that could be interpreted much more reliably: The abbreviated notation of the year (without the hundreds and thousands), which is often used, was de facto meaningless before the turn of the millennium, apart from the “loss” of the century.

    • 1/02/95 was clearly 1st day / 2nd month / 95th year almost worldwide
    • and collided 'only' with the USA: 1st month / 2nd day / 95th year

    On days after the 12th of every month this ambiguity was also excluded, since there is no month 13 (in the Gregorian calendar).

    • 02/15/60 was clearly February 15, 1960

    If the year is spelled completely, the uniqueness increases significantly today: 2001/02/03

    Only since 2013 has the danger of confusing the year ↔ month been banned again, and the uniqueness of the year will only be available again from 2032.

    standardization

    The following standards of national and international standardization organizations ( ISO , EN , and DIN standards ) applicable in German-speaking countries deal with the date format:

    • International standard ISO 8601 : 2004-12 Data elements and interchange formats - Information interchange - Representation of dates and times
      • Since September 2006 it has also been adopted with the same content as DIN ISO 8601.
    • German standard DIN 5008 : 2020-03 (Section 11.4) Writing and design rules for word and information processing

    ISO 8601 defines a basic structure for the exchange of date and time information, which consists exclusively of numerical components and does not use language-specific identifiers (words). Strict adherence to a given form is essential for the uniqueness of numeric dates. The essential feature of the basic structure specified in ISO 8601 is the "descending" arrangement in the form of year - month - day .

    example
    The calendar date of the seventh day of the first month in 2003 (January 7, 2003) in the ISO 8601 notation is:
    • 2003-01-07

    Alphanumeric dates, such as details with the full name of the month, are not the subject of ISO 8601. Such dates are still regulated in national standards, for example in DIN 5008. The alphanumeric notation recommended there is:

    • January 7, 2003

    Whether one or the other variant is used depends largely on the environment in which it is to be used. In a multinational and multilingual context, the ISO-compliant variant is recommended, while in a monolingual environment an alphanumeric variant can be used without any problems without impairing the uniqueness or comprehensibility.

    ISO 8601 and EN 28601

    In the ISO 8601 standard from 1988 an attempt was made to standardize the different national date formats. The result was a date format with a "descending" order (year-month-day) with short lines as separators, which was intended to replace the date formats with an "ascending" order (day-month-year) that were widely used until then.

    The ISO 8601 in 1992 without changes in the EN 28601: 1992 adopted the internal rules of CEN / CENELEC is mandatory for most European countries, as well as Germany , Austria and Switzerland . In December 2004, the new ISO 8601 replaced these standards. In addition, the standard has also been incorporated into the German standard DIN 5008 ( writing and design rules for word processing ).

    Date formats according to ISO 8601: 2004 using
    the example of the seventh day of the first month in 2003 (January 7, 2003)
    Complete representation
    20030107 YYYYMMDD Basic format
    2003-01-07 YYYY-MM-DD Extended format
    ( short dash as separator)
    Lower accuracy
    A certain month
    2003-01 YYYY-MM Basic format
    (short dash as separator)
    A specific year
    2003 YYYY Basic format
    YYYY = the digits here symbolize the year (from English : Year ), according to the Gregorian calendar
    MM = symbolizes the month (from English: Month )
    DD = symbolizes the day (from English: Day )
    In ISO 8601: 1988 and ISO 8601: 2000, so-called abbreviated representations were also defined, in which, for example, the century part of the year number can be omitted (YY-MM-DD). According to the current ISO 8601: 2004 standard, these representations are no longer permitted.
    In the IT sector , the hyphens are often left out in order to save memory space. Sometimes it is shortened further (YYMMDD).

    The new order was intended as a logical adjustment to the usually also "descending" order in our time specifications (hour-minute-second). In addition to the international standardization of the numerical format and the independence from a language, the "descending" arrangement facilitates correct sorting in lexicographical applications and in IT. The “descending” order simplifies the search for entries or files of a certain date. Further advantages are:

    • the possibility, improved by the "descending" format, of treating the complete date specification as a normal, long decimal number for purposes of filing and classification (highest digit on the left, lowest digit on the right);
    • the ability (with any numeric format) to perform arithmetic calculations in computer applications;
    • the possibility of logical continuation of the sequence by adding digits for hours , minutes and seconds, improved by the "descending" format .

    The disadvantage of the ISO 8601 standard is that the “descending” order (year-month-day) contradicts the common practice in many European languages ​​(with the exception of e.g. Hungary, Slovenia). In addition to Germany , the "ascending" order (day-month-year) is also common in French , Dutch , Italian , Spanish , Polish , Czech , Swedish , Danish and Turkish . Therefore, the new date format with its “descending” arrangement takes some getting used to for the user and has so far not been widely accepted in practice.

    DIN 5008

    The German standard DIN 5008 defines writing and design rules for text and information processing , which also include guidelines for the date format. EN 28601 of 1992, which is also valid for Germany, is also used for numerical dates.

    In the 1996 edition, the “new” format derived from ISO 8601 was adopted (via EN 28601) as the only correct numerical date notation. In addition, only the " alphanumeric spelling" with the full name of the month and without a preceding "0" for a single-digit number of days was permitted.

    However, the new date format according to the ISO standard (year-month-day) collided with actual writing habits and was not able to establish itself in the years from 1996 to 2000. Similar to most other European countries, the standard was largely ignored in Germany and Austria, where the usual format DD.MM. [YY] YY remained in use. In the 2001 edition of DIN 5008, a note was added, according to which the usual format should be permitted again, "provided that there are no misunderstandings". Since the 2011 edition, the year should only be given in four digits. The version of DIN 5008, published in 2020, only provides for the date in the format DD.MM.YYYY for letters to domestic recipients.

    Date formats according to DIN 5008: 2020-03 using
    the example of the seventh day of the first month in 2018 (January 7, 2018)
    Numerical notation
    preferred spelling 2018-01-07
    Optional spelling in letters to domestic recipients 07/01/2018
    Alphanumeric writing
    no leading zero for single-digit days
    written month name January 7, 2018
    Abbreviated month name (should not be used in running text) Jan. 7, 2018

    Time calculation information "v. Chr. "And" n. Chr. "

    The standard DIN 1355-1 (see DIN Pocket Book 102 of 1989), which was previously applicable in Germany, Austria and Switzerland and is still widely used today, saw the specification v. BC and AD in order to differentiate between years before and after the beginning of the Christian era . In the European standard EN 28601 from 1992, however, dating before or after Christ is no longer dealt with. In the version from the year 2000, ISO 8601 even provides for a year zero and years with a negative sign , whereby, in contrast to common usage, its switching method should also be applied retrospectively for the period before the introduction of the Gregorian calendar .

    See also

    Web links

    Individual evidence

    1. ↑ DIN 5008 : 2020-03, Section 11.4 "Dates"