Most of the time I use tns.ora file for Oracle connection.
But if i install oracle client or odac then tns.ora file is created and accessed.
but some time your client may not have that component. so i need direct connection string.
The syntax is:
string connectionString = "Data Source =(DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = oracle.dcl.net)(PORT = 1521)) )(CONNECT_DATA = (SERVICE_NAME = umrdb) )); User ID=rraquib; Password=rraquib";