Best solution for accessing multiple databases?

Good morning,

I’m currently running my Rails app out of PostgreSQL database but I’ve
gotten to a point where I need to query another Oracle database to
retrieve a single record.

I’ve seen approaches like this:
http://wiki.rubyonrails.org/rails/pages/HowtoUseMultipleDatabases

But is this the right method for me?

When a user uses my application it determines who they are via their
Windows Login. Using that login I have the capability to query an
Oracle database and retrieve all the information on that user. So when
the user logs into my application I would like to make the call to that
Oracle database, pull down their information and continue with the
application never having to access the Oracle database again.

Are there any other known methods out there that work very well?

Windows Login. Using that login I have the capability to query an
Oracle database and retrieve all the information on that user. So when
the user logs into my application I would like to make the call to that
Oracle database, pull down their information and continue with the
application never having to access the Oracle database again.

Why wouldn’t you setup the oracle database in database.yml then create a
model like ‘AllUserInfo’ or something that makes more sense and define
it
like this:

class AllUserInfo < ActiveRecord::Base
establish_connection ‘oracle_db_defined_in_yml_file’
set_table_name ‘whatever my table name is’
end

and then just do…

all_info_about_a_user = AllUserInfo.find(:first, :conditions…)

?

On 10/16/07, Matthew W. [email protected] wrote:

But is this the right method for me?

When a user uses my application it determines who they are via their
Windows Login. Using that login I have the capability to query an
Oracle database and retrieve all the information on that user. So when
the user logs into my application I would like to make the call to that
Oracle database, pull down their information and continue with the
application never having to access the Oracle database again.

Is there one Oracle DB or are there several and which one needs to be
determined based on the user or some other criteria? The article you
link to talks about the latter.

It it’s just one DB and you have one or more tables to be ‘statically’
connected to that DB , then see
http://rails.rubyonrails.com/classes/ActiveRecord/Base.html and look
for the section “Connection to multiple databases in different models”

You probably want to call establish_connection with the right
connection parameters for the table(s) to be connected to the oracle
DB in your config/environment.rb file in a config.after_initialize
block. If you’ve got several tables you can make an abstract AR class
for those models to subclass, and establish the connection for the
abstract class which will take care of the subclass.

I’m working on a project right now which does something similar. One
thing I’ve found is that most of the testing infrastructure of rails
doesn’t really handle tables with their own connections very well,
what I’ve done is to put analogs of those tables directly in the main
test environment database. I wrote the migrations for the ‘external’
tables so that they only actually create the tables if
ENV[‘RAILS_ENV’] is ‘test’


Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/

Philip H. wrote:

Windows Login. Using that login I have the capability to query an
Oracle database and retrieve all the information on that user. So when
the user logs into my application I would like to make the call to that
Oracle database, pull down their information and continue with the
application never having to access the Oracle database again.

Why wouldn’t you setup the oracle database in database.yml then create a
model like ‘AllUserInfo’ or something that makes more sense and define
it
like this:

class AllUserInfo < ActiveRecord::Base
establish_connection ‘oracle_db_defined_in_yml_file’
set_table_name ‘whatever my table name is’
end

and then just do…

all_info_about_a_user = AllUserInfo.find(:first, :conditions…)

?

I was unaware of this capability but it seems like the best bet.

That’s all I really need to do, it’s a single Oracle database with just
one lookup table that I need to access.

Thanks for the tip, I’ll give it a shot.

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