How do I read cx_Oracle.LOB data in Python?

Question

I have this code:

    dsn = cx_Oracle.makedsn(hostname, port, sid)
    orcl = cx_Oracle.connect(username + \'/\' + password + \'@\' + dsn)
    curs = orcl.cu         


        

Answer 1

I've found out that this happens in case when connection to Oracle is closed before the cx_Oracle.LOB.read() method is used.

orcl = cx_Oracle.connect(usrpass+'@'+dbase)
c = orcl.cursor()
c.execute(sq)
dane =  c.fetchall()

orcl.close() # before reading LOB to str

wkt = dane[0][0].read()

And I get: DatabaseError: Invalid handle!
But the following code works:

orcl = cx_Oracle.connect(usrpass+'@'+dbase)
c = orcl.cursor()
c.execute(sq)
dane =  c.fetchall()

wkt = dane[0][0].read()

orcl.close() # after reading LOB to str

Answer 2

There should be an extra comma in the for loop, see in below code, i have supplied an extra comma after x in for loop.

dsn = cx_Oracle.makedsn(hostname, port, sid)
orcl = cx_Oracle.connect(username + '/' + password + '@' + dsn)
curs = orcl.cursor()
sql = "select TEMPLATE from my_table where id ='6'"
curs.execute(sql)
rows = curs.fetchall()
for x, in rows:
    print(x)

Answer 3

You basically have to loop through the fetchall object

dsn = cx_Oracle.makedsn(hostname, port, sid)
orcl = cx_Oracle.connect(username + '/' + password + '@' + dsn)
curs = orcl.cursor()
sql = "select TEMPLATE from my_table where id ='6'"
curs.execute(sql)
rows = curs.fetchall()
for x in rows:
   list_ = list(x)
   print(list_)

Answer 4

Figured it out. I have to do something like this:

curs.execute(sql)        
for row in curs:
    print row[0].read()