Conenction in tns ORA file for conencting to Oracle data base

For conencting to Oracle database, First you need to create connection string in TNS ORA file.

1) go to C:\ORANT\NETWORK\ADMIN
2) Open tns names.ora file
3) Modify your variable in the following string
EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = HOSTNAME)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = PLSExtProc)
)
)