Re: [PHP] comparing time (related question)
On 24 Apr 2002, Jackson Miller wrote: When storing dates and times in databases is it better to store them as UNIX timestamps or in one of the SQL date/time types? I am working on an application that takes school attendance and has homework assignments, so I am doing a fair amount of date work. Currently I am storing everything as date time and referring to a day with the UNIX timestamp for midnight of that day. I am able to do everything I need to do with both formats, but I am wondering if there is a performance issue at hand. If you want to use your database's time functions for comparison or grouping when selecting data, then it usually makes sense to use the database's native time format. Easy enough to convert back and forth (it's usually cheaper to have the database convert to unix timestamps and to have PHP convert in the other direction, from timestamps to database format). miguel -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] comparing time (related question)
I think Miguel said it all: I will just add you this reference on mySQL (if that's what you use) field types reference. http://mysql.com/doc/D/a/Date_and_time_functions.html As of performance I'd say: The logic should be: Store all the data in DB so when you retrieve it you can do every comparison right within SQL having so raw data for PHP to layout on your pages. That is the first rule of dynamicity, and RDBMS (even if mySQL is kind of not...) usually count on such uses. Sincerely, Maxim Maletsky Founder, Chief Developer www.PHPBeginner.com // where PHP Begins -Original Message- From: Miguel Cruz [mailto:[EMAIL PROTECTED]] Sent: Wednesday, April 24, 2002 6:20 PM To: Jackson Miller Cc: [EMAIL PROTECTED] Subject: Re: [PHP] comparing time (related question) On 24 Apr 2002, Jackson Miller wrote: When storing dates and times in databases is it better to store them as UNIX timestamps or in one of the SQL date/time types? I am working on an application that takes school attendance and has homework assignments, so I am doing a fair amount of date work. Currently I am storing everything as date time and referring to a day with the UNIX timestamp for midnight of that day. I am able to do everything I need to do with both formats, but I am wondering if there is a performance issue at hand. If you want to use your database's time functions for comparison or grouping when selecting data, then it usually makes sense to use the database's native time format. Easy enough to convert back and forth (it's usually cheaper to have the database convert to unix timestamps and to have PHP convert in the other direction, from timestamps to database format). miguel -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] comparing time (related question)
On Wednesday, April 24, 2002, at 11:37 AM, Jackson Miller wrote: When storing dates and times in databases is it better to store them as UNIX timestamps or in one of the SQL date/time types? I am working on an application that takes school attendance and has homework assignments, so I am doing a fair amount of date work. Currently I am storing everything as date time and referring to a day with the UNIX timestamp for midnight of that day. I am able to do everything I need to do with both formats, but I am wondering if there is a performance issue at hand. As I recently discovered, it is much better to store them as a SQL date/time type, because your database will be better equipped to make complicated queries of the data if it is stored in the database's preferred data type. The flexibility of functions such as MySQL's DATE_FORMAT() or UNIX_TIMESTAMP() functions, and PHP's date() function, let you manipulate these numbers in any way you prefer for display, once the database has performed its work. Erik Erik Price Web Developer Temp Media Lab, H.H. Brown [EMAIL PROTECTED] -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
