With JDBC, we can use the following syntax to connect to an Oracle database over an LDAP connection:
jdbc:oracle:thin:#ldap://host:1234/service_name,cn=OracleContext,dc=org,dc=com
How can I connect over LDAP using cx_oracle?
I ended up going with jaydebeapi.
import pandas as pd
import jaydebeapi
import jpype
import os
import sys
def run(f_name,command,username,pw ):
jar='ojdbc8.jar'
args = '-Djava.class.path=%s' % jar
jvm_path = jpype.getDefaultJVMPath()
jpype.startJVM(jvm_path, args)
con = jaydebeapi.connect("oracle.jdbc.driver.OracleDriver", "jdbc:oracle:thin:#ldap://server.prod.company.com:3060/service,cn=OracleContext,dc=prod,dc=company,dc=com",[username, pw], jar)
try:
df= pd.read_sql(command,con)
df.to_excel(f_name)
print(df)
except Exception as e:
print(e)
finally:
con.close()
def Run_Program(myvars):
os.chdir(sys._MEIPASS)
f_name = myvars.MyFileName
command = myvars.plainTextEdit_CSVString.toPlainText()
username = myvars.lineEdit_UserName.text()
pw = myvars.lineEdit_Password.text()
run(f_name,command,username,pw )
Saving the ojdbc8.jar file from Oracle Client in the same folder and specifying the location in the code. And also downgrading the module JPype1 to JPype1==0.6.3 (its installed as a requirement for jaydebeapi )
This worked well for packaging using pyinstaller so that it could be shared. (i created a pyqt5 UI for user to use.
Here are my two cents using Python 3.7 and cx_Oracle v.8.2.0 on Win 10.
I wanted to issue queries to an Oracle database using Python, and what I already had was :
a username (or schema)
a password
a JDBC connection string that looked like:
jdbc:oracle:thin:#ldap://[LDAPHostname1]:[LDAPPort1]/[ServiceName],[DomainContext] ldap://[LDAPHostname2]:[LDAPPort2]/[ServiceName],[DomainContext]
where the [DomainContext] was of the form cn=OracleContext,dc=foo,dc=bar
First, you have to install cx_Oracle by following the Oracle documentation.
Note that:
cx_Oracle requires a series of library files that are part of the Oracle Instant Client "Basic" or "Basic Light" package (available here). Let's say we unzip the package under C:\path\to\instant_client_xx_yy
Depending on the platform you're on, some other requirements are to be filled (like installing some Visual Studio redistributable on Windows)
For the LDAP part, there are two configuration files that are required:
sqlnet.ora : This is the profile configuration file for Oracle, but mine was simply containing :
NAMES.DIRECTORY_PATH = (LDAP)
It tells the library to resolve names using LDAP only.
ldap.ora : This file tells where to look for when resolving names using LDAP. I knew I was accessing two OID servers, so mine was of the form :
DIRECTORY_SERVERS=([LDAPHostname1]:[LDAPPort1], [LDAPHostname2]:[LDAPPort2])
DEFAULT_ADMIN_CONTEXT="dc=foo,dc=bar"
DIRECTORY_SERVER_TYPE=oid
Important Note : I had to remove the cn=OracleContext from the DEFAULT_ADMIN_CONTEXT entry in order to make the name resolution work
Let's say those two files were saved under C:\path\to\conf
And now comes the Python part. I used the cx_Oracle.init_oracle_client() method in order to point to the library and configuration files. (Note that there are other ways to give cx_Oracle access to those files, like setting environment variables or putting those in predefined places. This is explained under the install guide)
Here is a little sample code:
import cx_Oracle
# username and password retrieved here
cx_Oracle.init_oracle_client(lib_dir=r'C:\path\to\instant_client_xx_yy', config_dir=r'C:\path\to\conf')
try:
with cx_Oracle.connect(user=username, password=password, dsn='[ServiceName]') as connection:
cursor = connection.cursor()
cursor.execute('SELECT * FROM ALL_TAB_COLUMNS')
# Outputs tables and columns accessible by the user
for row in cursor:
print(row[1], '-', row[2])
cursor.close()
except cx_Oracle.DatabaseError as e:
print("Oracle Error", e)
The short answer is that you use an ldap.ora configuration file and specify that it is to be used in your sqlnet.ora configuration file. Although this link talks about creating a database link and not directly connecting, the same principle applies and you can connect using any of the services referenced in your LDAP server.
http://technologydribble.info/2015/02/10/how-to-create-an-oracle-database-link-using-ldap-authentication/
Some more official documentation on how it works can be found here:
https://docs.oracle.com/cd/B28359_01/network.111/b28317/ldap.htm
Related
I'm trying to access oracle db in lambda using python using cx_Oracle library. Since oracle needs os specific client to connect, I also downloaded the instant client and add it as a layer in AWS. Problem is I'm seeing this error that wouldn't budge
DatabaseError: DPI-1047: Cannot locate a 64-bit Oracle Client library: "libclntsh.so: cannot open shared object file: No such file or directory"
lambda_handler.py
import cx_Oracle
import os
def lambda_handler(event, context):
dsn = cx_Oracle.makedsn('url', 1521)
con = cx_Oracle.connect(user='user', password='1234', dsn=dsn)
cursor = con.cursor()
cursor.execute('SELECT * FROM DEVICES')
return {
'statusCode': 200,
'body': cursor.fetchall()
}
I've seen other thread to add init_oracle_client, so I've addedcx_Oracle.init_oracle_client(lib_dir='/opt/instantclient_21_1')
since Lambda Layer is placed on "/opt" directory, it seems that it found the file, but it produces similar error. Notice the file different
DatabaseError: DPI-1047: Cannot locate a 64-bit Oracle Client library: "libnnz21.so: cannot open shared object file: No such file or directory"
According to my understanding, since I put the lib_dir specifically, the file supposed to be '/opt/instantclient_21_1/libnnz21.so' which is there, but for some reason Oracle try to find that library in the current runtime directory.
NOTE I'm using:
Python 3.8
Instant Client Lite for Linux x86-64
cx_Oracle-8.1.0-cp39-cp39-manylinux1_x86_64
I need to check oracle connectivity using python script.
My oracle connection string is in below format.
jdbc:oracle:thin:#ldap://ovd.mycomp.com:38901/cn=Oraclecontext,o=eus,dc=mycomp,dc=com/pidev ldap://ovd- mwdc.mycomp.com:38901/cn=Oraclecontext,o=eus,dc=mycomp,dc=com/pidev.
I tried https://dbajonblog.wordpress.com/2019/12/18/python-and-cx_oracle-for-oracle-database-connections/ but that did not help.
Could you please help me.
Thanks in advance.
The general cx_Oracle documentation on working with JDBC and Oracle SQL Developer Connection Strings has some info however if you're using LDAP you'll need to do some extra configuration. See https://stackoverflow.com/a/32151099/4799035 and https://github.com/oracle/node-oracledb/issues/1212#issuecomment-591940440 The steps are the same for cx_Oracle. Also see Connect to DB using LDAP with python cx_Oracle
I created following script using cx_oracle, which works fine.
only restriction is the dns name should be TNS entry.
Script:
import cx_Oracle
import sys
from botocore.exceptions import ClientError
connection = None
def isOracleHealthy(dbname, username, password, dns, log):
try:
sys.stderr.write(dns)
connection=cx_Oracle.connect("{}/{}#{}".format(username, password, dns))
cur=connection.cursor()
for result in cur.execute("SELECT * FROM dual"):
log.info(result)
return True
except Exception as e:
sys.stderr.write(dbname+' Oracle health check failed.\n')
log.error(dbname+' Oracle health check failed.')
return False
I need an R script that allows me to connect to an Oracle DB without having to install anything needing admin powers, and preferrably nothing at all apart from package downloads. In python the following code works, I believe because it uses the cx_Oracle module as a portable driver. What would be a good R alternative?
import pandas as pd
import sqlalchemy
import sys
host = "xxx.intra"
database = "mydb"
user = "usr"
password = "pw"
def get_oracle_engine(host, database, user, password):
return sqlalchemy.create_engine("oracle+cx_oracle://{user}:{password}#{host}:1521/?service_name={database}".format(host=host, database=database, user=user, password=password))
engine=get_oracle_engine(host, database, user, password)
pd.read_sql_table("mytable", engine, schema= mydb,index.cols="id1")
I managed to install ROracle using the CRAN instructions but I keep getting the ORA-12154 TNS: cound not resolve the connect identifier specified when using:
library(ROracle)
con= DBI::dbconnect(dbDriver("Oracle"), user= user, password=password, host=host, dbname=database, port="1521")
By the way dbDriver("Oracle") returns
Driver name : Oracle (OCI)
Driver version: 1.3-1
Client version: 12.1.0.2.0
Try code like:
library(DBI)
library(ROracle)
drv <- Oracle()
con <- dbConnect(drv, 'cj', 'welcome', 'localhost:1521/orclpdb1')
dbGetQuery(con,"select count(*) from dual")
The connect string components are related to the {host}:1521/?service_name values you used with SQLAlchemy. Use a TNS alias or Easy Connect String, the same as other C based Oracle drivers, e.g. https://cx-oracle.readthedocs.io/en/latest/user_guide/connection_handling.html#connection-strings
The current ROracle code is at https://www.oracle.com/database/technologies/roracle-downloads.html There are some packaging glitches with uploading to CRAN and the CRAN maintainers haven't been responsive about resolving them.
ROracle still needs Oracle Client libraries such as from Oracle Instant Client.
I'm on a W8 machine, where I use Python (Anaconda distribution) to connect to Impala in our Hadoop cluster using the Impyla package. Our hadoop cluster is secured via Kerberos. I have followed the API REFERENCE how to configure the connection.
from impala.dbapi import connect
conn = connect( host='localhost', port=21050, auth_mechanism='GSSAPI',
kerberos_service_name='impala')
We are using Kerberos GSSAPI with SASL
auth_mechanism='GSSAPI'
I have managed to install python-sasl library for WIN8 but still I encounter this error.
Could not start SASL: Error in sasl_client_start (-4) SASL(-4): no mechanism available: No worthy mechs found (code THRIFTTRANSPORT): TTransportException('Could not start SASL: Error in sasl_client_start (-4) SASL(-4): no mechanism available: No worthy mechs found',)
I wonder if I am still missing some dependencies.
Install the kerberos Python package, it will fix your issue.
I ran into the same issue but i fixed it by installing the right version of required libraries.
Install below python libraries using pip:
six==1.12.0
bit_array==0.1.0
thrift==0.9.3
thrift_sasl==0.2.1
sasl==0.2.1
impyla==0.13.8
Below code is working fine with the python version 2.7 and 3.4.
import ssl
from impala.dbapi import connect
import os
os.system("kinit")
conn = connect(host='hostname.io', port=21050, use_ssl=True, database='default', user='urusername', kerberos_service_name='impala', auth_mechanism = 'GSSAPI')
cur = conn.cursor()
cur.execute('SHOW DATABASES;')
result=cur.fetchall()
for data in result:
print (data)
Try this to get tables for kerberized cluster. In my case CDH-5.14.2-1.
Make sure you have a valid ticket before running this code.
with python 2.7 having below packages.
thrift-0.9.3
thriftpy-0.3.8
thrift_sasl-0.3.0
impyla==0.14.2.2
Working Code
from impala.dbapi import connect
from impala.util import as_pandas
# 21000 is impala daemon port.
conn = connect(host='yourHost', port=21050, auth_mechanism='GSSAPI')
cursor = conn.cursor()
cursor.execute("SHOW TABLES")
# After running .execute(), Impala will store the result sets on the server
# until it is fetched. Use the method .fetchall() to pull the entire result
# set over the network (you should only do it if you know dataset is small)
tables = cursor.fetchall()
print("Displaying list of tables")
# the result is a list of tuples
for t in tables:
# we know that each row in SHOW TABLES result
# should only contains one table name
print(t[0])
# exit() enable for only one table
print("eol >>>")
For me, installing this package fixed it: libsasl2-modules-gssapi-mit
For me, the following connection parameters worked. I did not have to install any additional packages in python.
connect(host="your_host", port=21050, auth_mechanism='GSSAPI', timeout=100000, use_ssl=False, ca_cert=None, ldap_user=None, ldap_password=None, kerberos_service_name='impala')
To connection Impala using python you can follow below steps,
Install Coludera ODBC Driver for Impala.
Create DSN using 64-bit ODBC driver, put your server details, below is sample screen shot for same
Use below code snippet for connectivity
import pyodbc
with pyodbc.connect("DSN=impala_con", autocommit=True) as conn:
... df = pd.read_sql("", conn)
python cannot connect hiveserver2
make sure you install cyrus-sasl-devel and cyrus-sasl-gssapi
I need to know how to query a table in sql server. Everywhere i look it says to use pyodbc but they didn't make one for 3.4 .
There isn't an official pyodbc for Python 3.4. However, as bernie mentions in his comment, you can try the 3.3 version. Additionally, the University of California, Irvine provides an unofficial build for pyodbc for Python 3.4. There is also the pypyodbc package, as an option.
In any case, once you decide on which to utilize, you can use it by doing something like this. Realize this a very simple query.
import pyodbc
# Create connection
con = pyodbc.connect(driver="{SQL Server}",server=SERVERNAME,database=DATA_BASE_INFO,uid=username,pwd=password)
cur = con.cursor()
db_cmd = "SELECT * FROM table_name"
res = cur.execute(db_cmd)
# Do something with your result set, for example print out all the results:
for r in res:
print r
In the line that beings con =, there are several values for you to fill in.
server needs to be server host information (either IP or DNS name), and possibly a port (default is 1435) "dns.to.host.com,1435"
uid is the username you are logging in with
pwd is the password of the user you are logging in with