-----BEGIN PGP MESSAGE----- Version: GnuPG v1.4.9 (GNU/Linux) owGbwMvMwCRor/UvqPLs4WbGNWZJkoZGRkaWJkYWFsaWRiZp6QXp8SW5BW6ZOake TxYsTEwqzs8pLUnNqVQoykzPKNEDAi4urg43FgZBJgY2ViaQIgYuTgGYkSovGObX 9Yfd+O70sEwjd7Vq3Zq9R1/zy0cyLOj+LXBqzeMNqnK/7h/rqwpaHppVvw4A =tzMr -----END PGP MESSAGE----- On Thu, Oct 2, 2008 at 3:37 PM, Jaka Jančar <[EMAIL PROTECTED]> wrote:
> Hi! > > MySQL (and probably others) has the following date/time types: > - TIME > - DATE > - DATETIME > - TIMESTAMP > > They each serve their purpose and are not redundant. Timestamp represents > an exact point in time. The others represent floating times, days, or times > within days. > > XML Schema also has a similar concept, where a dateTime (and therefore date > and time) can be timezoned or not. > > Zend_Date supports only timestamps. I like it that there is only one class, > for simplicity, but perhaps some properties like > - hasDate, > - hasTime and > - hasTimezone ( == !floating) > could be added and behavour of various functions (such as those for > comparing dates) adjusted to take these into account. > > What do you think? > > > (longer explanation:) > Why is this needed? > > Take, for example you want to store someone's birthday. Say it's > 1987-01-01. If you store it using Zend_Date, it becomes 1987-01-01 00:00 in > your current timezone (+02:00, for example). > > But the person most likely wasn't born at midnight, so, first of all, this > is semantically incorrect. > > There are also more practical problems. Say another user from another > timezone wants to see this person's birthday. If his timezone is +00:00 > he'll see 1986-12-31 22:00, which is obviously incorrect. > > To get around this, you'd have to: > - save Zend_Date's in UTC (or some other time zone) and remember to ignore > the timezone (== use the same one as when saving) when displaying them and > - don't show the time, since it's meaningless. > > If Zend_Date supported the options suggested above, you'd just set > hasDate=true, hasTime=false and hasTimezone=false, to get a floating date. > > > > -- Nilesh Govindrajan ([EMAIL PROTECTED]) iTech7 Site and Server Administrator www.itech7.com
