Mysql database access! possible without rails?

Ruby
1

Hello all, again,

I am very new to the ruby world and I’m trying to get a pretty simple
script to open a database connection read from it do stuff with the
data, write to it and finally close it. However, in the process I’ve
become very confused. Do i need rails to have the database connection?
I looked at JDBC and I can’t figure out how to tell it to open the
connection other than the database.yml file.
If someone could give me a tutorial link for getting the gem and
opening the connection, maybe even looping through the data, :slight_smile: that
would be great.

Thanks,

Paul

2

http://tel.jklm.no/2008/3/25/using-active-record-outside-rails

[sudo] gem install activerecord

require ‘active_record’

class County < ActiveRecord::Base
establish_connection :adapter => ‘mysql’,
:database => ‘db’,
:host => ‘localhost’,
:username => ‘user’,
:password => ‘pass’
end

irb(main):092:0> County.find(:all,
:limit => 5,
:order => ‘name’).map{|place| place.name}
=> [“Akershus”, “Aust-Agder”, “Buskerud”, “Finnmark”, “Hedmark”]

regards,
Tor Erik

3

Tor,

It didn't seem to work? I tried require active_record and it

“failed to find” it??? I’m using jruby/jirb but I tried with ruby/irb
as well and I got the same thing.

sudo jruby -S gem install activerecord
root’s password:
JRuby limited openssl loaded. gem install jruby-openssl for full
support.
http://wiki.jruby.org/wiki/JRuby_Builtin_OpenSSL
Updating metadata for 17 gems from http://gems.rubyforge.org
…
complete
Successfully installed activerecord-2.0.2
1 gem installed
Installing ri documentation for activerecord-2.0.2…
Installing RDoc documentation for activerecord-2.0.2…
jirb
irb(main):003:0> require ‘active_record’
LoadError: no such file to load – active_record
from (irb):4:in require' from (irb):4:in signal_status’

scripts/ruby # gem install activerecord
Need to update 16 gems from http://gems.rubyforge.org
…
complete
Install required dependency activesupport? [Yn] Y
Successfully installed activerecord-2.0.2
Successfully installed activesupport-2.0.2
Installing ri documentation for activerecord-2.0.2…
Installing ri documentation for activesupport-2.0.2…
Installing RDoc documentation for activerecord-2.0.2…
Installing RDoc documentation for activesupport-2.0.2…

irb
irb(main):002:0> require ‘active_record’
LoadError: no such file to load – active_record
from (irb):2:in `require’
from (irb):2

4

This is what I do to interact with my MySQL database w/o rails: First
install the mysql gem (c:/> gem install mysql)

require ‘mysql’
db = Mysql.connect(“localhost”, “username”, “password”, “database_name”)
@mysql_query = db.query(“YOUR SQL STATEMENT”)

#~ to iterate over results:
while row = @mysql_query.fetch_row do
@field1 = row[0]
@field2 = row[1]
#~ etc…

db.close

I think you have to have an ODBC connection set up, though. You can get
it from MySQL’s website.

Good luck,

  • Jeff M.
5

It didn’t seem to work? I tried require active_record and it
“failed to find” it??? I’m using jruby/jirb but I tried with ruby/irb
as well and I got the same thing.

require ‘rubygems’ before you require ‘active_record’

This is not neccesary if you are using the latest version of Ruby (1.8.6
something…)

regards,
Tor Erik

6

Hi Jeff,

Thanks for the clear direction, particularly for the Windows users. Can
you tell us where to find documentation for the mysql adapter?

Joseph Newton