How to connect to an Oracle database hosted on a different server from ksh script

This can be done two ways, by providing tns string inside the script or by placing it into tnsnames.ora file:

FILE1=output.log
sql="INSERT INTO TABLE1(...)VALUES(...);"
sqlplus 'username/pwd@@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=myHostname)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=myDB)))' << EOF > $FILE1
$sql
commit;
exit;
EOF

FILE1=output.log
sql="INSERT INTO TABLE1(...)VALUES(...);"
sqlplus 'username/pwd@DB_ALIAS' << EOF > $FILE1
$sql
commit;
exit;
EOF