cx_Oracle & Connecting to Oracle DB Remotely - cx-oracle

Question

How do you connect to a remote server via IP address in the manner that TOAD, SqlDeveloper, are able to connect to databases with just the ip address, username, SID and password?
Whenever I try to specify and IP address, it seems to be taking it locally.
In other words, how should the string for cx_Oracle.connect() be formatted to a non local database?
There was a previous post which listed as an answer connecting to Oracle via cx_Oracle module with the following code:
#!/usr/bin/python
import cx_Oracle
connstr='scott/tiger'
conn = cx_Oracle.connect(connstr)
curs = conn.cursor()
curs.execute('select * from emp')
print curs.description
for row in curs:
print row
conn.close()

Answer 1

I like to do it this way:
ip = '192.168.0.1'
port = 1521
SID = 'YOURSIDHERE'
dsn_tns = cx_Oracle.makedsn(ip, port, SID)
db = cx_Oracle.connect('username', 'password', dsn_tns)
One of the main reasons I like this method is that I usually have a TNSNAMES.ORA file lying around someplace, and I can check that the dsn_tns object will do the right thing by doing:
print dsn_tns
and comparing the output to my TNSNAMES.ORA

Answer 2

You can specify the server in the connection string, e.g.:
import cx_Oracle
connstr = 'scott/tiger#server:1521/orcl'
conn = cx_Oracle.connect(connstr)
"server" is the server, or the IP address if you want.
"1521" is the port that the database is listening on.
"orcl" is the name of the instance (or database service).

Answer 3

import cx_Oracle
CONN_INFO = {
'host': 'xxx.xx.xxx.x',
'port': 12345,
'user': 'user_name',
'psw': 'your_password',
'service': 'abc.xyz.com',
}
CONN_STR = '{user}/{psw}#{host}:{port}/{service}'.format(**CONN_INFO)
connection = cx_Oracle.connect(CONN_STR)

Answer 4

Instead of specifying the SID, you can create a dsn and connect via service_name like:
import cx_Oracle
ip = '192.168.0.1'
port = 1521
service_name = 'my_service'
dsn = cx_Oracle.makedsn(ip, port, service_name=service_name)
db = cx_Oracle.connect('user', 'password', dsn)
The benefit of using the service name instead of the specific instance identifier (SID), is that it will work in a RAC environment as well (using a SID won't). This parameter is available as of cx_Oracle version 5.1.1 (Aug 28, 2011)

Answer 5

import cx_Oracle
dsn = cx_Oracle.makedsn(host='127.0.0.1', port=1521, sid='your_sid')
conn = cx_Oracle.connect(user='your_username', password='your_password', dsn=dsn)
conn.close()

Answer 6

import cx_Oracle
ip = '172.30.1.234'
port = 1524
SID = 'dev3'
dsn_tns = cx_Oracle.makedsn(ip, port, SID)
conn = cx_Oracle.connect('dbmylike', 'pass', dsn_tns)
print conn.version
conn.close()