Rails to connect SQL SERVER is a more complicated matter. Since different platforms are different methods of treatment.

Take linux for a different release version has a different treatment methods.

Record ubuntu here under the rails to connect sqlserver steps.
Reference: http://wiki.rubyonrails.org/rails/pages/HowtoConnectToMicrosoftSQLServerFromRailsOnLinux

1 Edit ~ /. Bashrc file, add: 

export ODBCINI=/etc/odbc.ini
export ODBCSYSINI=/etc
export FREETDSCONF=/etc/freetds/freetds.conf


2 install unixODBC 

sudo apt-get install unixodbc unixodbc-dev tdsodbc


3 installed FreeTDS 

sudo apt-get install freetds-dev sqsh


Configure FreeTDS: Edit / etc / freetds / freetds.conf, add: 

[YOUR_DB_DEFINITION_NAME]
host = 192.168.1.101 (change this to the right one for you)
port = 1433
tds version = 8.0



Test FreeTDS: 

sqsh -S YOUR_DB_DEFINITION_NAME -U USERNAME -P PASSWORD


4 the definition of DB
Edit / etc / odbc.ini: 

[YOUR_DB_DEFINITION_NAME]
Driver = FreeTDS
Description = ODBC connection via FreeTDS
Trace = No
Servername = YOUR_DB_DEFINITION_NAME
Database = YOUR_ACTUAL_DB_NAME


Edit / etc / odbcinst.ini: 

[FreeTDS]
Description = TDS driver (Sybase/MS SQL)
Driver = /usr/lib/odbc/libtdsodbc.so
Setup = /usr/lib/odbc/libtdsS.so
CPTimeout =
CPReuse =
FileUsage = 1


Test: 

isql YOUR_DB_DEFINITION_NAME USERNAME PASSWORD


RUBY ODBC installation 5 

sudo apt-get install libodbc-ruby1.8


6 installed RBI ODBC DRIVER 

sudo gem install activerecord-odbc-adapter


The end of this installation.

databse.yml in this definition: 

development:
adapter: odbc
dsn: YOUR_DB_DEFINITION_NAME
username: USERNAME
password: PASSWORD



The above steps at ubuntu8.04, ruby1.8.6, rails 2.1, under the test.