CODEWITHSUNDEEP
pythonpython-2.7cx-oracle
Remy Sylve
Remy Sylve

Reputation: 33

cx_Oracle.DatabaseError: DPI-1039: statement was already closed

Upgraded to latest Cx_Oracle release (5.1.3 to 7.1.3) and now all my code is broken. Problem appears to be occurring when attempting to pass a cursor.

def select_query_remy(self,sql,params=None):
    with cx_Oracle.connect(self.connection) as con:
        cur = con.cursor()
        if params:
            cur.execute(sql,params)
        else:
            cur.execute(sql)
        #print cur.fetchall()
        return cur

I'm getting correct data in the fetchall so I know it is connecting properly and returning a valid result. So I comment it out.

In the other scripts I call it and rows should now store the cursor correct?

rows = con.select_query_remy(sql)

When I fetchall() from the other script I get below and get the error.

print rows.fetchall()

cx_Oracle.DatabaseError: DPI-1039: statement was already closed

Any ideas?

full db.py

import cx_Oracle

class db:

list ={}    

def __init__(self):
    '''
        AMFM Python DB connectors
   '''
    db.list["disprod"] = [999,"disprod.prod.com"]
    db.list["prodqry"] = [999,"prodqry.prod.com"]
    db.list["amfmprod"] = [999,"amfmprod.prod.com"]
    db.list["esriprod"] = [999,"esriprod.prod.com"]
    db.list["amfmtest"] = [999,"amfmtest.prod.com"]
    db.list["amfmdev"] = [999,"CCTdAMFM.prod.com"]
    db.list["amfmtran"] = [999,"amfmtran.prod.com"]


def setup(self,env, username, password):
    self.username = username
    self.password = password
    self.env = env

    self.port = db.list[env][0]
    self.ip = db.list[env][1]
    if env == "prodqry":
        self.env = "prodqry.world"
    elif env == "amfmprod":
        self.env = "amfmprod.world"
    elif env == "esriprod":
        self.env = "esriprod.world"
    else:
        self.env = env
    self.connection = self.username+"/"+self.password+"@"+self.ip+":"+str(self.port)+"/"+self.env

def select_query_remy(self,sql,params=None):
    with cx_Oracle.connect(self.connection) as con:
        cur = None
        cur = con.cursor()
        if params:
            cur.execute(sql,params)
        else:
            cur.execute(sql)
        return cur

In another python I create a new DB and try to get the cursor back.

con = db()
con.setup("xxx","user","password")
rows = con.select_query_remy(sql)
print rows.fetchall()

Result:

Traceback (most recent call last):
  File "C:\Python27\ArcGIS10.5\test\test.py", line 30, in <module>
    print rows.fetchall()
cx_Oracle.DatabaseError: DPI-1039: statement was already closed

If I return fetchall() the data comes across. When I pass the cursor itself the error occurs.

def select_query_remy(self,sql,params=None):
        with cx_Oracle.connect(self.connection) as con:
            cur = None
            cur = con.cursor()
            if params:
                cur.execute(sql,params)
            else:
                cur.execute(sql)
            #return cur
            return cur.fetchall()

Any ideas why can't I pass the cursor as it was done in the past?

Upvotes: 3

Views: 5889

Answers (2)

Nick Flores
Nick Flores

Reputation: 93

I ran into this error message when querying an Oracle database. I believe it happens if there are LOB (large objects) in the database, which hasn't been the case in all the Oracle databases that I have queried.

Since I am prototyping with Jupyter, I prefer to use context manager (with) statements, and this makes manipulating the query results much more difficult if I have to add a .close() statement in a separate cell.

My workaround for this was actually to use the builtin deepcopy function (I tried using .copy() but this did not work either. Any further manipulation/display of the data yielded the same error.

So my solution to you would be the following:

from copy import deepcopy
import cx_Oracle

def select_query_remy(self,sql,params=None):
    with cx_Oracle.connect(self.connection) as con:
        cur = con.cursor()
        if params:
            cur.execute(sql,params)
        else:
            cur.execute(sql)
        #print cur.fetchall()
        return deepcopy(cur.fetchall())

I believe this should solve your issue if it was the same one that I had.

Upvotes: 2

TrebledJ
TrebledJ

Reputation: 8987

Your error has to do with the with-block (also known as a context manager). Let me add a couple comments to the select_query_remy function:

def select_query_remy(self,sql,params=None):
    with cx_Oracle.connect(self.connection) as con:  # connects to database
        cur = None
        cur = con.cursor()
        if params:
            cur.execute(sql,params)
        else:
            cur.execute(sql)
        return cur                                # closes connection (invalidates cursor too!)

Since the with-block manages the context of the database connection, the connection will be closed after the block is exited.

To fix the error, I suggest performing fetchall inside the function directly then working with that data outside the function. (You have already kinda figured this out.)

Further Reading: The Python Language Reference: The with statement

Upvotes: 1

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