A little trap I blundered into each time I generated a Rails project with
$ rails example // Rails 2.x
$ rails new example // Rails 3.x
is that by default a generated project is configured to use a SQLite database. And so the configuration file for the databases looks as shown below (I omit the configurations for the “test” and “production” environments, as they are almost identical):
# example/config/database.yml
development:
adapter: sqlite3
database: db/development.sqlite3
pool: 5
timeout: 5000
This leads, of course, to an error as soon as you try to access the database while there is no such driver installed ;-)
To avoid this small problem, you have to specify the database type when using the “rails” command:
$ rails -d mysql example // Rails 2.x
$ rails new example -d mysql // Rails 3.x
This command then generates the following database.yml:
# example/config/database.yml
development:
adapter: mysql # Rails 3.x uses the mysql2 adapter
encoding: utf8
database: example_development
pool: 5
username: root
password:
socket: /var/run/mysqld/mysqld.sock
Happy Rails baking!
Update 2009-03-23: An alternative approach in Rails 2.x is to define the variable RAILS_DEFAULT_DATABASE with:
$ export RAILS_DEFAULT_DATABASE=mysql
Update 2011-02-20: Adapted for Rails3
When I started learning rails I used SQLite for the development. Works just fine. But there are certain pitfalls with SQLite on your development machine when you’re going to use MySQL in production:
If you use boolean values they are handled differently in SQLite and MySQL (That’s not a big problem because rails handles that for you – unless you use some complex queries as i did :( ). And certain functions are different: For exmple, it’s: RAND() in MySQL but RANDOM() in SQLite.
Just saying this because I spent a lot of time figuring out why my tests aren’t working as expected (development, production: MySQL, test: SQLite)
Well, anyway: I like how easy it is to set up a new project using SQLite.
@Andreas: Thanks for your comment!
Yes, such little incompatibilities between the databases can be annoying. Hence I prefer to use the same database type in all environments, as it eliminates a possible source of problems.
And yes, setting up a new project is quite smooth, even with MySQL (as soon as you learned about the “-d” option *g*).
Hi!
just wandering…
does anybody know how do you config rails to make mysql and not sqlite the default adapter?
thnx
@rbn: You can define the variable RAILS_DEFAULT_DATABASE and set it to mysql, see the hint I added to the article.
Hope that helps!
fantastic… :)) thank you very much for your kind and quick response!
@rbn: You are welcome!
[...] I got it from: http://cakebaker.42dh.com/2009/03/13/generating-a-rails-project-configured-to-use-mysql/ [...]
I wish everyone wrote clear, concise and direct posts like this!
@steve: You are welcome!
I’m using Windows Vista with Rails 3 and MySQL2, and the command was a little different in my case.
It is:
“rails new appname -d mysql”
Hope this helps, and thanks for the great post!
@Aaron: Thanks for your comment!
I adapted the article for Rails3.
Thank you very much for updating.
@sunswei: You are welcome :)
Hi,
i configured rails with mysql, but its not working.
development:
adapter: mysql2
encoding: utf8
reconnect: false
database: test [am able to connect to this DB]
pool: 5
username: root
password: root
host: localhost
Am getting the error as
“ActiveRecord::ConnectionNotEstablished”
Thanks!!!
@Varunkumar: Hm, it’s difficult to say what the cause of this error is. Maybe the accepted answer to Trouble getting Rails 3 to work with MySQL is helpful for you?
THANKS!