Wow, if I read that right, it means someone on the East coast submits answers to a test, it's somehow adjusted to be the same as someone who submits answers to a test from the west coast 3 hours later (time zone wise)? I can't possibly imagine how that works, but if it does that solves huge problems for me and I seriously owe you! I'm gonna do some more research so I understand how this works.
THANKS! -Brian _____ From: Peter Brawley [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 24, 2006 3:56 PM To: Brian Menke Cc: mysql@lists.mysql.com Subject: Re: Fun with Dates and Incentives. Brian, CURRENT_TIMESTAMP gives you time in your server's timezone. UTC_TIMESTAMP gives GM (universal) time, so dispenses with all timezone adjustments. Trouble is, you cannot use it as a defalt. You have to pass it as an INSERT value. PB ----- Brian Menke wrote: Peter, thanks for the detailed info. I will figure out how to get rid of the UNIQUE key. Somehow that got added. Thanks for the catch. As far as INT for student id goes, I'm using email because it will be unique, and offers an easy way to track a user through the app I'm building (user name, password, session id's etc.) but I do get what you are saying. Thanks for the UTC_TIMESTAMP suggestion. Although, since I haven't had a lot of experience, I don't really understand why it is better than CURRENT_TIMESTAMP. But. that's why I asked for advice :-) -Brian _____ From: Peter Brawley [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 24, 2006 1:31 PM To: Brian Menke Cc: mysql@lists.mysql.com Subject: Re: Fun with Dates and Incentives. Brian Re your schema, --it's redundant to define PRIMARY and UNIQUE keys on the same column, --why not an INT student id? --what if two (eg married) students share an email account? --comparing datetimes across multiple time zones will be simpler if you set completed_modules.time=UTC_TIMESTAMP in each new row of that table. That would give ... CREATE TABLE students ( id INT NOT NULL, -- auto_increment [simplest] or assigned by school? email varchar(64) NOT NULL, fname varchar(32) NOT NULL, lname varchar(32) NOT NULL, role char(2) NOT NULL default '5', password varchar(8) NOT NULL, phone varchar(24) default NULL, reg_date date default NULL, PRIMARY KEY (id), KEY email (email) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; CREATE TABLE completed_modules ( id INT NOT NULL, module_id char(2) NOT NULL default '', score INT NOT NULL default 0, time timestamp NOT NULL default CURRENT_TIMESTAMP ) ENGINE=InnoDB DEFAULT CHARSET=latin1; To find the first 10 scores of 100 on a particular module, just ... SELECT CONCAT(s.lname,', ',s.fname) AS Name, c.time, c.score FROM students s INNER JOIN completed_modules c USING (id) WHERE c.module_id = 1 AND c.score = 100 ORDER BY c.time ASC LIMIT 10; PB I'm hoping for some general advice on an approach for the following scenario: I have a customer who wants to put an incentive program in place for students taking learning modules and then completing tests. The concept is simple. Award the first 10 people who complete a test with a score of 100%... that type of thing. Students are allowed to take test more than once. Track each time the student takes the test and show the latest score ect. You get the idea. I have the database tables and relationships already all set up for the tests, but it's the tracking of the dates and times that I don't have and it got me thinking. I need to track down to the day/hour/minute level. Okay, that should be easy (I think). I'm going to need to do a lot of date/time calculations. Would it be best just to have a default of CURRENT_TIMESTAMP set for a TIMESTAMP field? Or, is their something else I should be using? I have limited experience having to munge and crunch date/time info and I want to make sure I have the flexibility to do what I need in the future. The next gotcha I thought up is what about different time zones. Obviously without this consideration, people on the East coast would have an unfair 3 hour advantage over people on the west coast. I guess I can have a time zone field in my student table so I could derive the time difference. Any suggestions on a good time zone approach? Here are my two tables as they stand now. I'm wondering if these are set up in a way to allow me to do all this date time crunching I'm going to need to do in the future? Any suggestions are greatly appreciated :-) CREATE TABLE `students` ( `store_id` varchar(6) NOT NULL, `email` varchar(64) NOT NULL, `fname` varchar(32) NOT NULL, `lname` varchar(32) NOT NULL, `role` char(2) NOT NULL default '5', `password` varchar(8) NOT NULL, `phone` varchar(24) default NULL, `reg_date` date default NULL, PRIMARY KEY (`email`), UNIQUE KEY `email` (`email`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; CREATE TABLE `completed_modules` ( `module_id` char(2) NOT NULL default '', `email` varchar(64) NOT NULL, `score` int(2) NOT NULL default '0', `time` timestamp NOT NULL default CURRENT_TIMESTAMP ) ENGINE=InnoDB DEFAULT CHARSET=latin1; Brian Menke Visual Matter, Inc 1445 Foxworthy Ave., Suite 50-215 San Jose, CA 95118 408 375 9969 San Jose ~ Los Angeles www.visualmatter.com _____ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.394 / Virus Database: 268.7.1/347 - Release Date: 5/24/2006 _____ No virus found in this incoming message. 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