Mysql storing lots of bit sized settings

Question

I have ~38 columns for a table.

ID , name , and the other 36 are bit-sized settings for the user.

The 36 other columns are grouped into 6 "settings", eg Setting1_on , Setting1_colored , etc.

Is this the best way to do this?

Thanks.

Answer 1

If it must be in one table and they're all toggle type settings like yes/no, true/false, etc... use TINYINT to save space.

I'd recommend creating a separate table 'settings' with 36 records one for each option. Then create a linking table to the user table with a value column to record the user settings. This creates a many-to-many link for the user settings. It also makes it easy to add a new setting--just add a new row to the 'settings' table. Here is an example schema. I use varchar for the value of the setting to allow for later setting which might not be bits, but feel free to use TINYINT if size is an issue. This solution will not use as much space as the one table with the danger of a large sparsely populated set of columns.

CREATE TABLE `user` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
   `name` varchar(64) DEFAULT NULL,
  `address` varchar(64) DEFAULT NULL,
  PRIMARY KEY (`id`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `setting` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(64) DEFAULT NULL,
   PRIMARY KEY (`id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8;


CREATE TABLE `setting_user` (
  `user_id` int(11) NOT NULL DEFAULT '0',
  `setting_id` int(11) unsigned NOT NULL,
  `value` varchar(32) DEFAULT NULL,
  PRIMARY KEY (`user_id`,`setting_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Answer 2

All depends on how you want to access them. If you want to (or must) just select one of them, then go with the @Ray solution. If they can be functionally grouped (really, not some pretend grouping for all those that start with F) ie. you'll always need number of them for a function and reading and writing them doesn't make sense as an individual flag, then perhaps storing them as ints and using logic operaoprs on them might be a goer.

Saying that, unless you are doing a lot of read and writes to the db during a session, bundling them up into ints gives you very little performance wise, it would save some space on the DB, if all the options had to exist. If doesn't exist = false, it could be a toss up.

So all things being unequal, I'd go with Mr Ray.

Answer 3

MySQL has a SET type that could be useful here. Everything would fit into a single SET, but six SETs might make more sense.

http://dev.mysql.com/doc/refman/5.5/en/set.html