Re: Using YY-MM-DD date input - Mailing list pgsql-general
From | Bruce Momjian |
---|---|
Subject | Re: Using YY-MM-DD date input |
Date | |
Msg-id | 200307252034.h6PKYLX20343@candle.pha.pa.us Whole thread Raw |
In response to | Re: Using YY-MM-DD date input (Tom Lane <tgl@sss.pgh.pa.us>) |
Responses |
Re: Using YY-MM-DD date input
(Tom Lane <tgl@sss.pgh.pa.us>)
Re: Using YY-MM-DD date input (Karsten Hilbert <Karsten.Hilbert@gmx.net>) |
List | pgsql-general |
Tom Lane wrote: > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > Does anyone use YY-MM-DD for date input? > > We are considering eliminating it for 7.4. You can still use > > yyyy-mm-dd, or course. > > The way I think the date input parser should work when seeing three > numeric values is: > > 1. If first field has four digits, then format is yyyy-mm-dd. OK > 2. If first field is larger than 31, assume format is yy-mm-dd. > (I'm not totally wedded to this, since it could be argued to be > allowing the input values to determine the interpretation, which > is exactly the kind of heuristic that people objected to in the > dd/mm vs mm/dd discussion last month. It seems reasonable to me, > but it could be removed without affecting the rest of this proposal.) I am not excited about this, though you could say it is an extension of the 4-digit rule. However, I don't like that 30-03-03 is in 2003 and 32-03-03 is in the year 32AD. That seems error-prone to me. :-) > 3. Otherwise, the format must be one of yy-mm-dd, dd-mm-yy, or mm-dd-yy. > We should use DateStyle to decide which one of these applies. I see this as a feature addition, because right now, in 2003, there is no way to enter a current date with a leading year using only two digits. Also, if there aren't many people who want it, I am concerned it will cause confusion, because our datestyle stuff is already complicated. > There are presently only two input DateStyles ('US' and 'European') but > it would be trivial to add a third to accept yy-mm-dd. We'd only need > to figure out what to call it. I'm tempted to just call it 'YMD' and > provide 'DMY' and 'MDY' as alternative names for 'US' and 'European'. Now, that is an interesting idea, and I wonder if they aren't better than US and European (and German), because they are more general. Is this something we want to do in feature freeze? > We could also use datestyle to decide what to do with ambiguous inputs > like 03-FEB-01 --- given a 3-way input DateStyle, I'd say YMD should > mean that the year is first, while the other two mean the day is first. Interesting. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
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