I used sqlalchemy to connect to the oracle server from python.
(cx_oracle installation and oracle instant client setup are completed.)
The code I used is as follows:
(I used the ip address instead of the hostname. The ip address is a sample value.)
engine = create_engine('oracle://scott:tiger#123.234.345.567:1521/sidname')
q = engine.execute(test_query)
q.fetchone()
But I got the error like below.
sqlalchemy.exc.DatabaseError: (cx_Oracle.DatabaseError) ORA-24454: client host name is not set
I didn't use hostname, but I don't know why this error occurred.
Shouldn't I use the ip address?
Is there a solution?
That error is about the configuration of the machine you are running SQLAlchemy on, not the syntax you are using. Using an IP address is OK.
Typically Linux users update /etc/hosts and add a hostname for the loopback address. If you update your question with system information, we can help more.
Related
I'm trying to connect to Amazon RDS Postgresql database with this python code
import psycopg2
engine = psycopg2.connect(
database="vietop2database",
user="postgres",
password="07041999",
host="vietop2.cf4afg8yq42c.us-east-1.rds.amazonaws.com",
port='5433'
)
cursor = engine.cursor()
print('opened database successfully')
I encountered an error:
could not connect to server: Connection timed out
Is the server running on host "vietop2.cf4afg8yq42c.us-east-1.rds.amazonaws.com" (54.161.159.194) and accepting
TCP/IP connections on port 5433?
I consulted this trouble shooting on amazon and I already make sure the DB instance's public accessibility is set to Yes to allow external connections. I also changed port to 5433 and set VPC security to default. Yet, I fail to connect to the database. What might be the reasons? Please help me. Thank you very much
Below are the database connectivity and configuration information
I found the answer. I need to add new inbound rule allowing all traffic of IPv4 type
I have a python application designed to pull data from a remote database server using pyodbc, then organize and display the data in a spreadsheet. I've had it working fine for several months now, with multiple coworkers in my department using it through a shared network folder.
My connection:
pyodbc.connect('DRIVER={SQL Server};
SERVER=<myServer_name>;
DATABASE=<myDB_name>;
UID=personsUser;
PWD=personsPassword')
A different employee within our same network recently tried to use the program and got this error:
pyodbc.Error: ('08001','[08001][Microsoft][ODBC SQL Server Driver]
[DBNETLIB]SQL Server does not exist or access denied. (17) (SQLDriverConnect)')
It looked like a simple permissions issue to me, so to confirm I replaced the userID and password with my own hardcoded in, but it gave the same error. Furthermore the same employee can log in and execute queries through SQL Server Management Studio without issue.
Since everyone else in our department can still use the application fine, I know it must be a client-side issue, but I just can't pinpoint the problem. Any input would be greatly appreciated, Thanks!
Updates:
Per flipperPA's answer below, I updated my connection string to include the port:
con = pyodbc.connect('''DRIVER={SQL Server};
SERVER=<myServer_name>;
PORT=1433;
DATABASE=<myDB_name>;
UID=personsUser;
PWD=personsPassword;''')
Unfortunately we still got the same error.
He is running 32-bit Windows 7 on an HP machine, the same setup as the rest of the group so it shouldn't to be an os-level issue.
He does operate SSMS on the same machine, but I ran through the telnet check just be sure - no issue there.
I've taught myself the pyodbc API and basic SQL, but I'm still relatively new to the underlying concepts of databases and remote connections. Could you explain the TDS driver a little more?
When including SERVER, I've found you often need to include the PORT as well; this is the most likely problem:
pyodbc.connect('DRIVER={SQL Server};
SERVER=<myServer_name>;
PORT=1433;
DATABASE=<myDB_name>;
UID=personsUser;
PWD=personsPassword')
I connect mostly from Linux, however. Could it be the other person is connecting from Mac OS/X or Linux? If so, they'll need to use the FreeTDS driver (MS provides one as well, but it is flaky, at best). If you continue to have problems, from the coworkers machine, make sure you can connect from the machine you're having issues with (unless its the same machine they can connect SSMS from):
telnet <myServer_name> 1433
If it connects, you're good, if it hangs on connecting, you're most likely looking at a firewall issue. Good luck!
After talking with a knowledgeable friend I was finally able to figure out my issue!
For some reason, the user's system was configured to connect using named pipes, but the server I was connecting to only had TCP/IP protocol enabled. The solution was to force the application to use TCP/IP by adding "tcp:" to the front of the server name.
The fixed connection string:
pyodbc.connect('''DRIVER={SQL Server};
SERVER=tcp:<myServer_name>;
PORT=1433;
DATABASE=<myDB_name>;
UID=personsUser;
PWD=personsPassword
''')
If for any of you still doesn't work you can try to refer the Localdb (if that's the case) by its pipe address.
If the DB name is LocalDBA, in cmd type
SqlLocalDB LocalDBA v
Get the instance pipe name and then put it on the server name:
conn_str = (
r'DRIVER={SQL Server};'
r'SERVER=np:\\.\pipe\LOCALDB#ECE5B7EE\tsql\query;'
r'PORT=1433;'
r'DATABASE=VT-DE;'
r'trusted_connection=yes;'
)
I previously wrote my app using local development servers, and now that I have moved it onto an openshift small gear almost all works except for mysql connections.
In my code I have the line:
self.db = MySQLdb.connect(host, username, password, dbname)
When I review the openshift error log, the following error is reported:
_mysql_exceptions.OperationalError: (2002, "Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)")
I think that python is trying to connect using a UNIX socket as opposed to an INET one, but I'm not sure how to change this behavior. Any help is much appreciated.
Not specific to MySQLdb: if you use localhost as hostname, a MySQL client using the MySQL C libraries will try to connect using UNIX socket (or named pipe on Windows). There are 2 ways around this, but you'll need to grant extra permissions to make it work for both:
Use IP address 127.0.0.1
Use IP address 127.0.0.1 instead of the localhost hostname. This will make MySQL client connect using TCP/IP.
Use option files
The other way is to force the protocol using using option files. For example, in your ~/.my.cnf (or any file you want), add the following:
[python]
protocol=tcp
Now use the connection arguments to read the option file and group:
import MySQLdb
cnx = MySQLdb.connect(host='localhost', user='scott', passwd='tiger',
read_default_file='~/.my.cnf',
read_default_group='python')
The group name does not need to be python, but it is good not to use mysql or client as it might interfere with other MySQL tools (unless you want that of course).
For setting up permissions, you'll need to use the IP address of localhost, something like:
mysql> GRANT SELECT TO yourdb.* TO 'scott'#'127.0.0.1' IDENTIFIED BY ...;
(Site note: MySQL database drivers such as MySQL Connector/Python do not consider localhost to be special and connect through TCP/IP right away and you have to explicitly use the unix_socket.)
As I later discovered, while the database server runs on localhost, it runs on a very specific localhost bind address. In my case it was an address that I would never have though to try if I hadn't noticed how phpmyadmin was connecting.
db = MySQLdb.connect(host ="host",
user="user",
passwd="pass",
db="dbname")
q = db.cursor()
So, that's my code block, I was just wondering, how easy would this be to reverse engineer, and does mysqldb send authentications over cleartext?
I am creating a program that connects to a mySQL server over the internet, would someone be able to get my credentials?
Would someone be able to get my server login details?
The MySQL server could be configured to use SSL to secure the connection. See here for an example of using MySQLdb with an SSL connection and here for some info on configuring the server.
In your example above the username, password and all other data would be sent in cleartext.
Here are two related questions Python MySQLDB SSL Connection , CA SSL parameter for Python MySQLdb not working, but key does?
If you have access to change configure the MySQL server, we can help configure SSL.
MySQL supports encrypted connections. The MySQL server you are connecting to must be configured to use SSL and the client must add an SSL parameter when connecting.
Using SSL connections
shell> mysql --ssl-ca=ca-cert.pem ...
You can test if the server you are connecting to supports SSL my adding --ssl-ca=ca-cert.pem.
ca-cert.pem: Use this as the argument to --ssl-ca on the server and client sides. (The CA certificate, if used, must be the same on both sides.)
MySQL SSL Example describes the process from setting up MySQL for and connecting with SSL.
Passwords shouldn't be hardcoded in the code. Python has the convention of a config.py module, where you can keep such values separate from the rest of your code.
Please have a look here:
http://dev.mysql.com/doc/refman/5.5/en/connector-python-coding.html
The question regarding SSL to prevent disclosure has been answered above.
Fabio
#fcerullo
i'm trying to connect my local XMPP server by the code coming below
import xmpp
client = xmpp.Client('localhost',debug=[])
client.connect(server=('localhost',5222))
but i always get this message :
An error occurred while looking up _xmpp-client._tcp.localhost
i've checked that the port 5222 is already opened(by using telnet).
(i have to mention that the firewall on the localhost is off)
now what should i add to this code to make it work ?
This message (a warning, not an error as pointed out in xinox's answer) is indicating that a DNS SRV record lookup failed. DNS SRV records are used to find services that are associated with a certain domain (eg. localhost in this case, so not really a domain at all which is why the lookup is failing), but which delegate their responsibility to a server living somewhere else.
For instance, if I have a server at example.net, making my Jabber ID (JID): user#example.net, but my XMPP server lived at chat.example.net I could construct an SRV record on example.net to point to chat.example.net. There are other ways to delegate responsibility, but this is the preferred one. XMPPs use of SRV records is defined in RFC 6120 ยง3.2.1.
To actually get rid of this error you can use the use_srv kwarg, making your initial example:
import xmpp
client = xmpp.Client('localhost',debug=[])
client.connect(server=('localhost',5222), use_srv=False)
use this.
client = xmpp.Client('127.0.0.1',debug=[])
client.connect(server=('127.0.0.1',5222))
or your IP 192.X.X.X