purpose of tnsnames.ora

Hi

I would like to know the purpose of tnsnames.ora .Can some explain how it contact the data base and features

Thanks
lnr

The TNSNAMES.ORA file describes to Net8 how to communicate with your database. It is commonly referred to as an "alias" file. Basically, you define a database and the user can refer to it using the alias. For example, If I had the following entry in my TNSNAMES.ORA file:
DEV815NT.US =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = mydbserver)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = dev815nt.us)
)
)

I could access my database by:
sqlplus [email protected]