How to connect to MSSQL from Linux using ODBC

Following steps has been tested in CentOS 5 and Redhat Enterprise Server

To connect to MSSQL 2005 server from linux machine,unixODBC and freeTDS packages has to be installed.

[$] yum list unixODBC*

Loaded plugins: downloadonly, rhnplugin, security
Excluding Packages in global exclude list
Finished
Available Packages
unixODBC.i386                      2.2.11-7.1              
unixODBC-devel.i386                2.2.11-7.1               
unixODBC-kde.i386                  2.2.11-7.1               

Install following packages

[$] yum install unixODBC.i386

[$] yum install unixODBC-devel.i386

Once ODBC has been installed,install FreeTDS

[$] yum list freetds*

Loaded plugins: downloadonly, rhnplugin, security
Excluding Packages in global exclude list
Finished
Available Packages
freetds.i386               0.64-1.1.rs     
freetds-unixodbc.i386      0.64-1.1.rs     
freetds-devel.i386         0.64-1.1.rs     
freetds-doc.i386           0.64-1.1.rs

[$] yum install freetds.i386
[$] yum install reetds-unixodbc.i386

Once you have completed installation

Edit /etc/odbc.ini file by adding a DNS configuration as shown below(Create a new file if it doesn't exists).

[MSSQLDB]
Driver = FreeTDS
Description = MS SQL DNS
Trace = Yes
TraceFile = /var/log/mstest.log
Servername = MSSQLDB_SERVER
Database =
Port = 1433

Open /etc/odbcinst.ini file and confirm that driver configuration for FreeTDS exists otherwise add following entry

[FreeTDS]
Description     = FreeTDS unixODBC Driver
Driver          = /usr/lib/libtdsodbc.so.0
Setup           = /usr/lib/libtdsodbc.so.0
UsageCount      = 2

Please not that the name FreeTDS has been refered in /etc/odbc.ini file as Driver

Now we have to configure Free TDS with host and port number of the database.To do that edit /etc/freetds.conf

[MSSQLDB_SERVER]
host = 
port = 1433
tds version = 8.0

Please not that the name MSSQLDB_SERVER has been refered in /etc/odbc.ini file as Servername.

Now we are done with configuration.To check the connection try

[$] isql MSSQLDB  

above command should give following result if you could connect to MSSQL server successfully

+---------------------------------------+
| Connected!                            |
|                                       |
| sql-statement                         |
| help [tablename]                      |
| quit                                  |
|                                       |
+---------------------------------------+
SQL>

References

FreeTDS

UnixODBC