Mysql database access! possible without rails?

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

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

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:insignal_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

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.

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

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

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