Talk:Epoch

message: I have removed the line in the table for January 1, 0, because there are no citations. Details follow.
Symbian appears to be effectively defunct, which makes it hard to obtain information about it. I was not able to locate any documentation that seemed likely to address the epoch.
"Turbo DB" is difficult to identify. A web search returns results for seemingly different products.
MATLAB has a few different ways to represent dates. http://www.mathworks.com/help/matlab/ref/datenum.html states "The datenum function creates a numeric array that represents each point in time as the number of days from January 0, 0000. The numeric values also can represent elapsed time in units of days. However, the best way to represent points in time is by using the datetime data type." This seems to contradict the information in the article, and also makes it doubtful whether a date associated with the datenum function should be mentioned in the article when MathWorks seems to consider the datetime data type superior. Jc3s5h (talk) 17:32, 8 April 2015 (UTC)
replies: text: Datetime was only introduced in R2014b; before that version MATLAB only used serial dates, so the entry was accurate when it was added. The document by Moler (http://www.mathworks.com/moler/intro.pdf formerly cited on the page) still uses the datenum function, and was last updated 2013. Given that MATLAB serial dates are still important in legacy applications (and in its open-source clone Octave) I would recommend restoring it. Arcorann (talk) 04:57, 25 April 2015 (UTC)
replies: text: Documentation has been located for Symbian. Turns out the correct date should be 1 January, 1 CE (not 0 CE). The page appears to be a copy of the official documentation; the original source is unknown. At any rate, the page gives enough info to locate a source suitable for Wikipedia. Arcorann (talk) 05:13, 25 April 2015 (UTC)
replies: text: So I found a more recent version of the same documentation and it turns out it's contradicting itself. This page on date and time handling claims 0 CE, while the page corresponding to the earlier link still states 1 CE. At this point I no longer have the motivation to research further. Arcorann (talk) 05:33, 25 April 2015 (UTC)
thread_title: No citations for January 1, 0

message: how do you say this in english?
* like epic: IPA ɛpɪk
* like eepock: IPA iːpɔːk
please, someone who knows, edit this in as in this article: Heidi  — Preceding unsigned comment added by OsamaBinLogin (talk • contribs) 05:42, 6 February 2016 (UTC)
thread_title: Pronunciation

message: In these edits User:Kevinthenerd added an epoch for the Oracle Database of January 1, 4712 BC. There are several problems with this edit.
The source says "A Julian day number is the number of days since January 1, 4712 BC. This is false. A reliable source, Richards (see footnote 4 in article) states "The Julian Day Number ... of Tuesday −4712 January 1 is 1." (p. 592) (By the way, Richards is only correct if it is understood that January 1, &minus4712, is stated in the Julian calendar, not the Gregorian calendar).
The Oracle source also gives this example:
:Example This statement returns the Julian equivalent of January 1, 1997:
:SELECT TO_CHAR(TO_DATE('01-01-1997', 'MM-DD-YYYY'),'J')
:    FROM DUAL;
:TO_CHAR
:--------
:2450450
But for the same date, the Multiyear Interactive Computer Almanac from the US Naval Observatory provides this result:
                           CALENDAR                            
     
   Date        Time       Day      Julian Date      Day-of-Year
         (TT)                         (TT)             (TT)
          d  h  m   s                    d              d
1997 Jan 01 00:00:00.0    Wed     2450449.500000       1.000000
So I conclude the source is too poor to figure out what the epoch is for the Oracle Database and a better source is required. Accordingly, I have reverted the edits. Jc3s5h (talk) 21:41, 12 May 2016 (UTC)
replies: text: Does the Oracle database treat these dates as integers, floating point, or what? Could it be a matter of rounding? What time zone does it use, if any? Jc3s5h (talk) 22:16, 14 September 2020 (UTC)

text: Also, in the years since the edits in question were made, computer-related epochs have been moved to Epoch (computing). Jc3s5h (talk) 22:22, 14 September 2020 (UTC)
replies: text:  As per the documentation (version 20 here), the DATE data type of the Oracle database stores dates internally as a tuple of (year, month, day, hour, minute, second). Storing time zone information requires TIMESTAMP WITH TIME ZONE, but this data type is also a tuple. Thus, the Oracle database does not have an epoch. The above commands use the database software's conversion capabilities to convert to/from a date format ("J", representing Julian days). Arcorann (talk) 15:12, 15 September 2020 (UTC)
thread_title: Dubious source for Oracle database epoch

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