Connect to db2 database with Python
Question:
I’m working on an app that needs to connect to an ibm db2 database. Using DBeaver I can successfully connect to the database (I provide him the db2cc.jar and db2cc4.jar files).
It looks to me as DBeaver is using my Window’s credentials to login, because I didn’t need to input any login or password to connect.
Now, I’ve been trying to connect to the same database using python 3.7 and pypi’s latest version of the ibm_db package. I didn’t install anything else.
import ibm_db
# ...
connection_string = "DATABASE=" + self.params['schema'] + ";" +
"HOSTNAME=" + self.params['host'] + ";" +
"PORT=" + self.params['port'] + ";" +
"PROTOCOL=TCPIP;" +
"SECURITYMECHANISM=4;" +
"UID=" + self.params['user'] + ";" +
"PWD=" + self.params['password'] + ";"
try:
self.connection = ibm_db.connect(connection_string, "", "")
# ...
Using my Windows credentials in the parameters, I get the following error message:
Connection error
Bad credentials
SQLCODE=-30082
08001
From what I’ve seen on stack overflow connecting to a db2 database is complicated…
Does someone know how to connect ? Using the windows credentials or otherwise…
Thanks !
Answers:
Try the following connection string, If your db2 client and server are on the same host.
Change the ‘mydb’ and ‘DB2’ (db2 instance name, you can get it with db2ilist utility) constants according your case.
ibm_db.connect('DATABASE=mydb;Instance=DB2;PROTOCOL=IPC;', '', '')
Db2 works fine with Python, i.e. with cpython.
You need to be aware of some basics before you start such as:
- what operating-system runs the target Db2-database (Z/OS, i series, Linux/Unix/Windows/cloud) and
- what kind of client is being used (java, odbc/cli, .net etc), and
- what kind of authentication/encrpytion is in place for the database
(ssl, server based authentication/+/-/encryption etc.).
- is the remote database rdbms Apache DERBY or Db2.
Find out these basics before you start. You have to speak with people who run the Db2-server. If your target database is on Db2 on cloud, then
Note: in your question you mention (SecurityMechanism=4) i.e com.ibm.db2.jcc.DB2BaseDataSource.USER_ONLY_SECURITY – this is not relevant for non-JAVA clients, it is relevant if the database manager is DERBY .
For python, the ibm_db package is not a java application, it is a python extension written in the ‘c’ programming language. In fact, the python ibm_db extension is a wrapper for an underlying CLI driver (which does the real work of communicating with the database).
DBeaver is a java application (hence it uses a driver specifically for java, for example it uses either db2jcc.jar or more typically db2jcc4.jar and a licence-file to connect to the remote database, for certain platforms).
You can only use your Microsof-Windows credentials for connecting to a Db2-database either when that Db2-database runs on a Microsoft-Windows server, or when the Db2-server is confugured to integrate with Microsoft Active-Directory, and those credentials also work on the hostname running the Db2-server or Active-Directory.
For any other combinations (of Db2-client operating system, and Db2-server operating system), the server administrator (or security people) must issue you a userid/password that works on the target Database-server environment.
The ibm_db package needs a Db2-client to be installed, and by default it will automatically install IBM’s clidriver package unless you explicitly tell the installer not to do that installation.
A Db2-client can also be separatly installed before python , if you so wish, in which case you must tell Python installer to not install clidriver, by setting environment variable IBM_DB_HOME before installing ibm_db as described in the readme. Typically the reason you would re-use a preexisting Db2-client for python is that your existing Db2-client is already configured with ODBC data source names (DSNs) for your databases and any licenses that might be needed. In that case python ibm_db would be able to reuse without reconfiguration.
There are different kinds of Db2-client available from IBM depending both on which operating-system runs your Db2-server and how much functionality you need to have in your Db2-client. At least two other non-IBM companies supply ODBC drivers for Db2-clients.
If your remote Db2-server runs on Linux, Unix, Windows or Z/OS then you can use the "IBM Data Server Runtime Client" which you can either download from IBM’s passport advantage website, or get from your internal IT folks.
If your Db2-server runs on i-Series (AS/400) you should get its drivers from your i-Series administrator (the package IBM i access is available with an ODBC option).
For both Z/OS targets or i-Series targets you will additionally need a license file (which costs money) and you should get that from your administrator, unless your company uses a gateway product called Db2-connect in which case you don’t need a separate license file on your workstation.
add ibm_db library and import ibm_db on top in the .py file.
def get_db_connection():
"""
This will help to get db2 connection for query execution
:return: conn
"""
dsn_driver = "{IBM DB2 ODBC DRIVER}"
dsn_database = "BLUDB"
dsn_hostname = "your_hostname"
dsn_port = "50000"
dsn_protocol = "TCPIP"
dsn_uid = "your_userid"
dsn_pwd = "your_pwd"
dsn = (
"DRIVER={0};"
"DATABASE={1};"
"HOSTNAME={2};"
"PORT={3};"
"PROTOCOL={4};"
"UID={5};"
"PWD={6};").format(dsn_driver, dsn_database, dsn_hostname, dsn_port, dsn_protocol, dsn_uid, dsn_pwd)
try:
conn = ibm_db.connect(dsn, "", "")
print("Connected!")
return conn
except Exception:
print("nERROR: Unable to connect to the '" + dsn_database + "' server.")
print("error: ", ibm_db.conn_errormsg())
exit(-1)
function get_db_connection() will return the connection object. On that connection object you can perform operation like:
conn = get_db_connection()
list_results = []
select_query = 'SELECT a.STATUS, a.ID FROM "TABLE_NAME" AS a'
print(select_query)
selectStmt = ibm_db.exec_immediate(conn, select_query)
while ibm_db.fetch_row(selectStmt) != False:
list_results.append(ibm_db.result(selectStmt, 'ID'))
ibm_db.close(conn)
I’m working on an app that needs to connect to an ibm db2 database. Using DBeaver I can successfully connect to the database (I provide him the db2cc.jar and db2cc4.jar files).
It looks to me as DBeaver is using my Window’s credentials to login, because I didn’t need to input any login or password to connect.
Now, I’ve been trying to connect to the same database using python 3.7 and pypi’s latest version of the ibm_db package. I didn’t install anything else.
import ibm_db
# ...
connection_string = "DATABASE=" + self.params['schema'] + ";" +
"HOSTNAME=" + self.params['host'] + ";" +
"PORT=" + self.params['port'] + ";" +
"PROTOCOL=TCPIP;" +
"SECURITYMECHANISM=4;" +
"UID=" + self.params['user'] + ";" +
"PWD=" + self.params['password'] + ";"
try:
self.connection = ibm_db.connect(connection_string, "", "")
# ...
Using my Windows credentials in the parameters, I get the following error message:
Connection error
Bad credentials
SQLCODE=-30082
08001
From what I’ve seen on stack overflow connecting to a db2 database is complicated…
Does someone know how to connect ? Using the windows credentials or otherwise…
Thanks !
Try the following connection string, If your db2 client and server are on the same host.
Change the ‘mydb’ and ‘DB2’ (db2 instance name, you can get it with db2ilist utility) constants according your case.
ibm_db.connect('DATABASE=mydb;Instance=DB2;PROTOCOL=IPC;', '', '')
Db2 works fine with Python, i.e. with cpython.
You need to be aware of some basics before you start such as:
- what operating-system runs the target Db2-database (Z/OS, i series, Linux/Unix/Windows/cloud) and
- what kind of client is being used (java, odbc/cli, .net etc), and
- what kind of authentication/encrpytion is in place for the database
(ssl, server based authentication/+/-/encryption etc.). - is the remote database rdbms Apache DERBY or Db2.
Find out these basics before you start. You have to speak with people who run the Db2-server. If your target database is on Db2 on cloud, then
Note: in your question you mention (SecurityMechanism=4) i.e com.ibm.db2.jcc.DB2BaseDataSource.USER_ONLY_SECURITY – this is not relevant for non-JAVA clients, it is relevant if the database manager is DERBY .
For python, the ibm_db package is not a java application, it is a python extension written in the ‘c’ programming language. In fact, the python ibm_db extension is a wrapper for an underlying CLI driver (which does the real work of communicating with the database).
DBeaver is a java application (hence it uses a driver specifically for java, for example it uses either db2jcc.jar or more typically db2jcc4.jar and a licence-file to connect to the remote database, for certain platforms).
You can only use your Microsof-Windows credentials for connecting to a Db2-database either when that Db2-database runs on a Microsoft-Windows server, or when the Db2-server is confugured to integrate with Microsoft Active-Directory, and those credentials also work on the hostname running the Db2-server or Active-Directory.
For any other combinations (of Db2-client operating system, and Db2-server operating system), the server administrator (or security people) must issue you a userid/password that works on the target Database-server environment.
The ibm_db package needs a Db2-client to be installed, and by default it will automatically install IBM’s clidriver package unless you explicitly tell the installer not to do that installation.
A Db2-client can also be separatly installed before python , if you so wish, in which case you must tell Python installer to not install clidriver, by setting environment variable IBM_DB_HOME before installing ibm_db as described in the readme. Typically the reason you would re-use a preexisting Db2-client for python is that your existing Db2-client is already configured with ODBC data source names (DSNs) for your databases and any licenses that might be needed. In that case python ibm_db would be able to reuse without reconfiguration.
There are different kinds of Db2-client available from IBM depending both on which operating-system runs your Db2-server and how much functionality you need to have in your Db2-client. At least two other non-IBM companies supply ODBC drivers for Db2-clients.
If your remote Db2-server runs on Linux, Unix, Windows or Z/OS then you can use the "IBM Data Server Runtime Client" which you can either download from IBM’s passport advantage website, or get from your internal IT folks.
If your Db2-server runs on i-Series (AS/400) you should get its drivers from your i-Series administrator (the package IBM i access is available with an ODBC option).
For both Z/OS targets or i-Series targets you will additionally need a license file (which costs money) and you should get that from your administrator, unless your company uses a gateway product called Db2-connect in which case you don’t need a separate license file on your workstation.
add ibm_db library and import ibm_db on top in the .py file.
def get_db_connection():
"""
This will help to get db2 connection for query execution
:return: conn
"""
dsn_driver = "{IBM DB2 ODBC DRIVER}"
dsn_database = "BLUDB"
dsn_hostname = "your_hostname"
dsn_port = "50000"
dsn_protocol = "TCPIP"
dsn_uid = "your_userid"
dsn_pwd = "your_pwd"
dsn = (
"DRIVER={0};"
"DATABASE={1};"
"HOSTNAME={2};"
"PORT={3};"
"PROTOCOL={4};"
"UID={5};"
"PWD={6};").format(dsn_driver, dsn_database, dsn_hostname, dsn_port, dsn_protocol, dsn_uid, dsn_pwd)
try:
conn = ibm_db.connect(dsn, "", "")
print("Connected!")
return conn
except Exception:
print("nERROR: Unable to connect to the '" + dsn_database + "' server.")
print("error: ", ibm_db.conn_errormsg())
exit(-1)
function get_db_connection() will return the connection object. On that connection object you can perform operation like:
conn = get_db_connection()
list_results = []
select_query = 'SELECT a.STATUS, a.ID FROM "TABLE_NAME" AS a'
print(select_query)
selectStmt = ibm_db.exec_immediate(conn, select_query)
while ibm_db.fetch_row(selectStmt) != False:
list_results.append(ibm_db.result(selectStmt, 'ID'))
ibm_db.close(conn)