DB connection(cx_Oracle) function calling from another function gives "AttributeError: 'NoneType' object has no attribute 'cusror'" - oracle

Question

I have two python files and each have one function :
a.py (This function is for oracle db connection)
def db_conection(username,password,dbname,encoding):
# print(username,password,dbname,encoding)
try:
connection = cx_Oracle.connect(username, password, dbname, encoding=encoding)
# show the version of the Oracle Database
print(connection.version)
except cx_Oracle.Error as error:
print(error)
finally:
# release the connection
if connection:
connection.close()
b.py
from a import *
def set_schema(user):
con = db_conection(username,password,dbname,encoding)
cur = con.cursor()
print(user)
cur.execute("""alter session set current_schema = {}""".format(user))
cur.close()
user = "ABCDE"
set_schema(user)
The problem/error i am facing when i try to execute set_schema function(b.py)
cur = con.cursor()
AttributeError: 'NoneType' object has no attribute 'cursor'
if i just run below statment in b.py for set_schema function it works
db_conection(username,password,dbname,encoding)

Answer 1

The direct "solution" is:
# a.py
def db_conection(username,password,dbname,encoding):
try:
connection = cx_Oracle.connect(username, password, dbname, encoding=encoding)
# show the version of the Oracle Database
print(connection.version)
return connection
except cx_Oracle.Error as error:
print(error)
and
# b.py
from a import *
def set_schema(user):
con = db_conection(username,password,dbname,encoding)
con.current_schema = user # more efficient then executing ALTER
user = "ABCDE"
set_schema(user)
Of course, once db_connection() has finished the connection will be closed, but hopefully you just gave example code to show your problem. You may want to look at subclassing.
If you are running multi-user, you could use a connection pool and use a session callback to set session attributes.