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Running a python script with prepared statement gives me no errors but doesn't do what I expect [duplicate]

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psycopg2 not actually inserting data
(2 answers)
Closed 2 months ago.
I am running this python code to read in quotes from a file and then insert each quote into a table in my database. When I run the script in my terminal there are no errors but when I go to the database table I tried to insert to it tells me there are 0 rows.
#!/usr/bin/python
import psycopg2
import re
from config import config
conn = psycopg2.connect(
host="localhost",
database="favorite_quotes",
user="postgres",
password="???")
data = None
with open('file.txt', 'r') as file:
data = file.read()
list_of_strings = re.findall('“(.+?)” \(.+?\)', data, re.DOTALL)
def insert_quotes():
""" Connect to the PostgreSQL database server """
conn = None
try:
# read connection parameters
params = config()
# connect to the PostgreSQL server
print('Connecting to the PostgreSQL database...')
conn = psycopg2.connect(**params)
# create a cursor
cur = conn.cursor()
for str in list_of_strings:
cur.execute("INSERT INTO the_courage_to_be_disliked (quote) VALUES (%s)", [str])
# execute a statement
# dblist = list(cur.fetchone())
# quotes = []
# for row in cur:
# quotes.append(row[1])
# return quotes
# close the communication with the PostgreSQL
cur.close()
except (Exception, psycopg2.DatabaseError) as error:
print(error)
finally:
if conn is not None:
conn.close()
print('Database connection closed.')
if __name__ == '__main__':
insert_quotes()

You aren't committing your inserts, so they won't be visible from outside the current connection, and will be implicitly rolled back when the connection is closed.
TL;DR, add a call to conn.comimt() before calling conn.close().

Python with psycopg2 and pgAdmin4 how can i retrieve bytea data

I have uploaded a jpg image with the bytes() function to the bytea field.
INSERT CODE
conn = None
try:
# read data from a picture
imagen = open("imagen.jpg", "rb").read()
# connect to the PostgresQL database
conn = psycopg2.connect(host="localhost", database="test", user="postgres", password="admin")
# create a new cursor object
cur = conn.cursor()
# execute the INSERT statement
cur.execute("INSERT INTO nuevotest(id,data) " +
"VALUES(%s,%s)",
(1, bytes(imagen)))
# commit the changes to the database
conn.commit()
# close the communication with the PostgresQL database
cur.close()
except (Exception, psycopg2.DatabaseError) as error:
print(error)
finally:
if conn is not None:
conn.close()
SELECT CODE:
conn = None
try:
conn = psycopg2.connect(host="localhost", database="test", user="postgres", password="admin")
# create a new cursor object
cur = conn.cursor()
# execute the INSERT statement
cur.execute(""" SELECT data
FROM nuevotest
WHERE id=1 """,
)
# commit the changes to the database
conn.commit()
imagen = cur.fetchall()
print(type(imagen))
print(imagen)
# close the communication with the PostgresQL database
cur.close()
except (Exception, psycopg2.DatabaseError) as error:
print(error)
finally:
if conn is not None:
conn.close()
But what i was expectiong was a list or tuple with the byte code, not this:
PyCharm console with a (memory direction? idk)
I have no idea how to work with that.

Depends on what you are planning on doing after you retrieve the data. As #adrian_klaver said, you can use a buffer to write the output. Like this you would send it to a file:
with open(your_output_file, 'wb') as im:
im.write(the_in_memory_data)
Using PIL you can output it to the image viewer of the system without saving it.

PYTHON MYSQL doesn't work second time

Am receiving json data (from an other python script) to put inside MYSQL database, the code work fine the first time but the second time I got this error:
raise errors.OperationalError("MySQL Connection not available.")
mysql.connector.errors.OperationalError: MySQL Connection not available.
For troubleshooting am sending always the same data, but it still write an error the second time.
I tried also from information found on furums to place : cur = mydb.cursor() at diferents places but I have never been able to get this code work the second time.
There is my code :
import mysql.connector
import json
mydb = mysql.connector.connect(
host="localhost",
user="***",
passwd="***",
database="***"
)
def DATA_REPARTITION(Topic, jsonData):
if Topic == "test":
#print ("Start")
INSERT_DEBIT(jsonData)
def INSERT_DEBIT(jsonData):
cur = mydb.cursor()
#Read json from MQTT
print("Start read data to insert")
json_Dict = json.loads(jsonData)
debit = json_Dict['debit']
print("I send")
print(debit)
#Insert into DB Table
sql = ("INSERT INTO debit (data_debit) VALUES (%s)")
val=debit,
cur.execute(sql,val)
mydb.commit()
print(cur.rowcount, "record inserted.")
cur.close()
mydb.close()
Thanks for your help!

You only open your database connection once, at the start of the script, and you close that connection after making the first insert. Hence, second and subsequent inserts are failing. You should create a helper function which returns a database connection, and then call it each time you want to do DML:
def getConnection():
mydb = mysql.connector.connect(
host="localhost",
user="***",
passwd="***",
database="***")
return mydb
def INSERT_DEBIT(jsonData):
mydb = getConnection()
cur = mydb.cursor()
# Read json from MQTT
# rest of your code here...
cur.close()
mydb.close()

Python MySQL - Returning Cursor and Connection from Function

Previously I've always used something like...
def getConn():
cnx = mysql.connector.connect(user='user', password='pass',
host='hostIP',
database='database')
cur = cnx.cursor(buffered=True)
return [cnx, cur]
To return cnx and cur objects for use. That works fine.
I now need to use an SSH connection to a DB.
The example below executes the query within the function, but won't return the cnx or cur objects for use afterwards, so I get a print of the result, followed by the error
mysql.connector.errors.InterfaceError: 2013: Lost connection to MySQL server during query
I appear to be having the same issue (although a different error returned) to Why won't Python return my mysql-connector cursor from a function?
That question deals with why - I'd like to know if there is a solution.
def returnConnect():
mypkey = paramiko.RSAKey.from_private_key_file('/Users/me/.ssh/id_rsa')
sql_hostname = '127.0.0.1'
with SSHTunnelForwarder(
(ssh_host, ssh_port),
ssh_username=ssh_user,
ssh_pkey=mypkey,
remote_bind_address=(sql_hostname, sql_port)) as tunnel:
cnx = mysql.connector.connect(host='127.0.0.1', user=sql_username,
passwd=sql_password, db=sql_main_database,
port=tunnel.local_bind_port)
cur = cnx.cursor(buffered=True)
sql = "select * from table"
cur.execute(sql)
result = cur.fetchall()
print result
return [cnx, cur]
conn = returnConnect()
cnx = conn[0]
cur = conn[1]
sql = "select * from table"
cur.execute(sql)
result = cur.fetchall()
cnx.close()
print result

Python calls special method __exit__ after with..as execution, so your connection closes after returning from the context of with. Assign the tunnel forvarder to a variable like follow and you`ll be able to use the connection outside the function scope
tunnel = SSHTunnelForwarder(
(ssh_host, ssh_port),
ssh_username=ssh_user,
ssh_pkey=mypkey,
remote_bind_address=(sql_hostname, sql_port))
Read more about compound with statement in the docs.

PyMySQL Error inserting values into table. - Python

I am trying to make a login system with python and mysql. I connected to the database, but when I try to insert values into a table, it fails. I'm not sure what's wrong. I am using python 3.5 and the PyMySQL module.
#!python3
import pymysql, sys, time
try:
print('Connecting.....')
time.sleep(1.66)
conn = pymysql.connect(user='root', passwd='root', host='127.0.0.1', port=3306, database='MySQL')
print('Connection suceeded!')
except:
print('Connection failed.')
sys.exit('Error.')
cursor = conn.cursor()
sql = "INSERT INTO login(USER, PASS) VALUES('test', 'val')"
try:
cursor.execute(sql)
conn.commit()
except:
conn.rollback()
print('Operation failed.')
conn.close()

I think it may have to do with the order of the statements in the connection. According to the PyMySQL github (found here) the correct order is host, port, user, passwd, db.

Like this :
user = input("User: ")
pass = input("Pass: ")
sql = "INSERT INTO login(USER, PASS) VALUES('%s', '%s')"%(user, pass)
btw you should connect like this :
conn = pymysql.connect(
host='127.0.0.1',
user='root',
passwd='root',
db='MySQL
)