# Noob Question - Migrations **URL:** \ **Category:** Rails\ **Created:** [April 3, 2008, 3:00pm UTC](https://www.ruby-forum.com/t/noob-question-migrations/133779 "2008-04-03T15:00:55Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Rory\_McKinley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@Rory\_McKinley](https://www.ruby-forum.com/u/Rory_McKinley)\ **Post date:** [April 3, 2008, 3:00pm UTC](https://www.ruby-forum.com/t/noob-question-migrations/133779/1 "2008-04-03T15:00:55Z")
Hello list If I am using migrations to build my Db schema, is there any way to generate fixed-length fields for MySQL (i.e. char instead of varchar). I have tried STFW, but have come back with nothing to say that it is possible, but nothing that conclusively states it is impossible. Thanks ---
**Author:** ![Rory\_McKinley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@Rory\_McKinley](https://www.ruby-forum.com/u/Rory_McKinley)\ **Post date:** [April 3, 2008, 3:11pm UTC](https://www.ruby-forum.com/t/noob-question-migrations/133779/2 "2008-04-03T15:11:34Z")
t.column :fieldname, :string, :limit =\> 10 On Thu, Apr 3, 2008 at 11:30 PM, Rory McKinley [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > – Ryan B. > **[frozenplague.net](http://www.frozenplague.net)** > > This domain may be for sale! Feel free to add me to MSN and/or GTalk as this email. ---
**Author:** ![Rory\_McKinley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@Rory\_McKinley](https://www.ruby-forum.com/u/Rory_McKinley)\ **Post date:** [April 3, 2008, 4:40pm UTC](https://www.ruby-forum.com/t/noob-question-migrations/133779/3 "2008-04-03T16:40:59Z")
Ryan B. (Radar) wrote: > t.column :fieldname, :string, :limit =\> 10 Thanks Ryan But if I read my docs correctly - wouldn’t that create a VARCHAR(10)? When what I need is a CHAR(10). Regards Rory ---
**Author:** ![Rory\_McKinley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@Rory\_McKinley](https://www.ruby-forum.com/u/Rory_McKinley)\ **Post date:** [April 4, 2008, 7:36am UTC](https://www.ruby-forum.com/t/noob-question-migrations/133779/4 "2008-04-04T07:36:31Z")
I just tried doing t.column :fieldname, :char, :limit =\> 10 and it worked for me, you might as well give it a shot too. On Fri, Apr 4, 2008 at 1:09 AM, Rory McKinley [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Regards > > Rory > > > – Ryan B. > **[frozenplague.net](http://www.frozenplague.net)** > > This domain may be for sale! Feel free to add me to MSN and/or GTalk as this email. ---
**Author:** ![Rory\_McKinley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@Rory\_McKinley](https://www.ruby-forum.com/u/Rory_McKinley)\ **Post date:** [April 4, 2008, 8:51am UTC](https://www.ruby-forum.com/t/noob-question-migrations/133779/5 "2008-04-04T08:51:55Z")
Ryan B. (Radar) wrote: > I just tried doing t.column :fieldname, :char, :limit =\> 10 and it worked > for me, you might as well give it a shot too. Hi Ryan Unfortunately, it didn’t work for me: A migration script that looks like this: create\_table(:users, :options=\> ‘ENGINE MyISAM DEFAULT CHARACTER SET UTF8’) do |t| t.column :first\_name, :char, :limit =\> 10, :null =\> false t.column :last\_name, :char, :limit =\> 10, :null =\> false t.column :permission\_goal\_super, :boolean, :null =\> false t.column :permission\_milestone\_super, :boolean, :null =\> false end Produces a table that looks like this: CREATE TABLE `users` ( `id` int(11) NOT NULL auto\_increment, `first_name` char(1) NOT NULL, `last_name` char(1) NOT NULL, `permission_goal_super` tinyint(1) NOT NULL, `permission_milestone_super` tinyint(1) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 It seems that if you use :char you are limited to exactly that - a character ;). One workaround I have found is to manually add character columns post creation using the execute method. ---
**Author:** ![Rory\_McKinley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@Rory\_McKinley](https://www.ruby-forum.com/u/Rory_McKinley)\ **Post date:** [April 4, 2008, 12:26pm UTC](https://www.ruby-forum.com/t/noob-question-migrations/133779/6 "2008-04-04T12:26:38Z")
Why must it be a char field type? surely varchars are just as good, unless it’s a life-or-death situation to making your database as small as possible. On Fri, Apr 4, 2008 at 5:20 PM, Rory McKinley [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Produces a table that looks like this: > It seems that if you use :char you are limited to exactly that - a > character ;). > > One workaround I have found is to manually add character columns post > creation using the execute method. > > > – Ryan B. > **[frozenplague.net](http://www.frozenplague.net)** > > This domain may be for sale! Feel free to add me to MSN and/or GTalk as this email. ---
**Author:** ![Rory\_McKinley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@Rory\_McKinley](https://www.ruby-forum.com/u/Rory_McKinley)\ **Post date:** [April 4, 2008, 2:13pm UTC](https://www.ruby-forum.com/t/noob-question-migrations/133779/7 "2008-04-04T14:13:04Z")
Fair enough. Glad to see you found your own solution. 🙂 On Fri, Apr 4, 2008 at 9:19 PM, Rory McKinley [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Actually, varchars in mysql will on average use less space than a char > field, unless you are maxing out your field length every time. But, > varchars infer performance penalties when used as part of an index. From > a DB design POV, it is a good idea to minimise the use of varchars. > > I worked around, by using execute - works like a charm! > > > – Ryan B. > **[frozenplague.net](http://www.frozenplague.net)** > > This domain may be for sale! Feel free to add me to MSN and/or GTalk as this email. ---
**Author:** ![Rory\_McKinley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@Rory\_McKinley](https://www.ruby-forum.com/u/Rory_McKinley)\ **Post date:** [April 4, 2008, 12:50pm UTC](https://www.ruby-forum.com/t/noob-question-migrations/133779/8 "2008-04-04T12:50:19Z")
Ryan B. (Radar) wrote: > Why must it be a char field type? surely varchars are just as good, unless > it’s a life-or-death situation to making your database as small as possible. Hi Ryan Actually, varchars in mysql will on average use less space than a char field, unless you are maxing out your field length every time. But, varchars infer performance penalties when used as part of an index. From a DB design POV, it is a good idea to minimise the use of varchars. I worked around, by using execute - works like a charm!