MySQL Database Unique Column Names

Question

I have written myself a PHP script to help manage a small squad of 10 members. This script current connects to a database and updates weekly updating any rank and power change. However I want to expand this and in a new table, have all the power gained kept in a separate column instead of adding it all up.

The only way I can think of doing this is by using the below code to create the column and changing the name for each.

ALTER TABLE `power gained` ADD timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP AFTER name;

So my question is, can I create columns making sure their name is unique, OR is it possible to set a column name to the timestamp as that would save me a column.

I'd like to also make it clear I am using mysql_ functions as this is on my local system, not vulnerable to attacks and I am not stupid enough to make mistakes.

Answer 1

Use normalisation.

Split the users and the power into two difference tables.

CREATE TABLE `users_power` (
  `user_id` smallint(5) NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL,
  `total_power` int(11) NOT NULL DEFAULT '1',
  PRIMARY KEY (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;

CREATE TABLE `power` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` smallint(1) NOT NULL,
  `time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `power_increase` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1;

DROP TRIGGER IF EXISTS `Update users_power`;

CREATE TRIGGER `Update users_power` AFTER INSERT ON `power` FOR EACH ROW BEGIN
    UPDATE `users_power` AS `UP`
    SET `UP`.`total_power` = `UP`.`total_power` + NEW.`power_increase`
    WHERE `UP`.`user_id` = NEW.`user_id`;
END

And then to look up, do something like;

SELECT `power` AS total_power
FROM users_power
WHERE users_power.`user_id` = 1

And your structure would look something like;

select * from power where user_id = 1;
+----+---------+---------------------+----------------+
| id | user_id | time                | power_increase |
+----+---------+---------------------+----------------+
|  1 |       1 | 2014-08-7 17:04:06  |              5 |
|  2 |       1 | 2014-08-15 17:04:31 |             15 |
+----+---------+---------------------+----------------+
2 rows in set

select * from users_power where user_id = 1;
+---------+------+-------------+
| user_id | name | total_power |
+---------+------+-------------+
|       1 | joe  |          21 |
+---------+------+-------------+
1 row in set

Edits

• Added trigger to automatically update total power when a record is inserted into power

Answer 2

Haven't yet tested this but I think I have found a way I can do this in a way that I understand (which is the most important part).

$now = date('Y-m-d');
mysql_query("ALTER TABLE `power gained` ADD `$now` VARCHAR(22) AFTER name");
// ...
mysql_query("UPDATE `power gained` (`$now`) VALUES($gained) WHERE id = $i");

I'm not looking to extract the data from the database as I can access it just by going to localhost/phpmyadmin and I'm not going to ever need to extract it.