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 J
>
>
>
> -Brian
>
>
>
> ------------------------------------------------------------------------
>
> *From:* Peter Brawley [mailto:peter.brawley@stripped]
> *Sent:* Wednesday, May 24, 2006 1:31 PM
> *To:* Brian Menke
> *Cc:* mysql@stripped
> *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 <http://www.visualmatter.com>
>
>
>
>
>
>
>
>
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>
>
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