support@xxxxxxxxxxxxxxxxxxxxxx schreef:
>> On Monday, December 15, 2008 7:29 PM, gouldimg@xxxxxxx wrote:
>>
...
> <?php
>
> error_reporting(E_ALL);
> ini_set('error_reporting', E_ALL);
> ini_set('display_startup_errors','1');
> ini_set('display_errors','1');
>
>
> function dec2base($dec)
> {
> $digits = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
> $value = "";
> $base = strlen($digits);
> while($dec>$base-1)
> {
> $rest = $dec % $base;
> $dec = $dec / $base;
> $value = $digits[$rest].$value;
> }
>
> $value = $digits[intval($dec)].$value;
> return (string) $value;
> }
>
> /*
> // Step 1) define database connection
>
> define('DB_HOST', 'localhost'); // Change this to the proper DB Host name
> define('DB_USERNAME', 'myusername'); // Change this to the proper DB User
> define('DB_PASSWD', 'mypassword'); // Change this to the proper DB User
> password
> define('DB_NAME', 'mydatabase'); // Change this to the proper DB Name
>
> @mysql_connect(DB_HOST, DB_USERNAME, DB_PASSWD) or die("Error: Database
> connection information is incorrect");
> @mysql_select_db(DB_NAME) or die("Error: Database connection information
> is incorrect");
>
> */
>
> /*
> // Step 2) create test schema
>
> CREATE TABLE IF NOT EXISTS `test` (
> `id` int(11) NOT NULL auto_increment,
> `mykey` varchar(20) NOT NULL,
> PRIMARY KEY (`id`)
> ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
>
> */
>
>
> /*
> // Step 3) create 700,000 records
>
> for ($i=1; $i <= 700000; $i++)
> {
> @mysql_query("INSERT INTO test VALUES ('', '')");
> }
>
> */
>
> /*
> // Step 4) update 700,000 records
>
>
> // The larger this number is detrmines the size of "mykey"
> $int = 1000000;
>
> $result = @mysql_query("SELECT id FROM test ORDER BY id ASC");
>
> if (@mysql_num_rows($result) > 0)
> {
> while ($row = @mysql_fetch_object($result))
> {
> // Add the two numbers together and base it
> $mykey = dec2base($int+$row->id);
> @mysql_query("UPDATE test SET mykey='".$mykey."' WHERE
> id='".$row->id."'");
> }
> }
>
> */
or just:
mysql_query("UPDATE test SET mykey=UUID()");
can't see any reason to go down the 'loop the dataset and roll your
own much less random, much more likely to collide, unique value' road.
sometimes less is more (although oddly more is never less ;-)
just be sure to read the docs regarding charsets and indexes to make
sure you don't inadvertently create a performance problem (due to
unused indexes):
http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_uuid
> ?>
>
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