I have a code like this:
import mysql.connector as mysql
from generate_records import generateRecords
devicesQuery = "CALL iot.sp_sensors_overview()"
try:
db = mysql.connect(
user = "username",
password = "password",
host = "hostname",
database="iot"
)
cursor = db.cursor(dictionary=True, buffered=True)
cursor.execute(devicesQuery)
for sensor in cursor:
generateRecords(sensor, db)
cursor.close()
except mysql.connector.Error as error:
print("Error:")
print(error)
else:
db.close()
The purpose of generateRecords function is obviously to generate records and run the INSERT query against the different table.
Seems like I do something wrong, because no matter what I trying, I getting different errors here, like mysql.connector.errors.OperationalError: MySQL Connection not available..
(upd) I also tried to change the code like it was suggested (see example bellow), with no luck - I still receiving the MySQL connection not available. error.
rows = cursor.fetchall()
cursor.close()
for sensor in rows:
cursor2 = db.cursor()
generateRecords(sensor, cursor2)
So, should I create a new connection within generateRecords function, or pass something different within it, or use some kind of different approach here?
Thank you!
Finally I found what was wrong. I'm used the query to call the stored procedure. Using the cursor.callproc("sp_sensors_overview") instead fixed my issue, and now I'm able to create the next cursor without errors.
Related
I'm trying to query a MySQL DB to retrieve a list of variables. Am I doing something wrong here?
# import required modules
import pymysql.cursors
# Connect to the database
connection = pymysql.connect(host='123.12.123.12',
port=3306,
user='db_user',
password='db_pass',
database='db_mcmods',
cursorclass=pymysql.cursors.DictCursor)
with connection:
with connection.cursor() as cursor:
# Read a single record
#Setting variables as n,v,l to use later.
sql = "SELECT `master_mods`.`Name` AS n, `master_mods`.`Version` AS `n`, `master_mods`.`Link` AS `n` FROM `master_mods`"
cursor.execute(sql)
numrows = cursor.rowcount()
for x in xrange(0,numrows):
row = cursor.fetchone()
print(row[x])
This is the error that my DB throws:
(HY000/1045)
Things I have tried:
Checked DB User Permissions
Checked Connection Values
Fixed Mismatched encoding between DB & Table
Ran query through PHPMyAdmin to check validity
Here is my
Table Structure
Ok, so I figured it out and forgot to post the answer. It ended up being a weird error with cpanel, I had to reset my database user pw twice before it ended up working.
TL;DR Password issue. Appreciate the help everyone.
I have this super simple Python code to connect to Postgres and to create a schema. It shows no error but I don't see the schema being added in Postgres. I must be missing something that's apparent.
I am not even sure if this's connected to Postgres because when I gave it a wrong password, it still returned without errors. But when it keeps saying connection is in place when I do trial and error. Please help~ thanks!
import psycopg2
psycopg2.autocommit = True
def build_archive(db1):
db1 = psycopg2.connect(database='postgres', user='operator', password='1234', host='localhost', port='2280')
cursor = db1.cursor()
sql = """CREATE SCHEMA app_tools AUTHORIZATION operator;"""
cursor.execute(sql)
No where in your code do you actually call build_archive() so the code inside of it is never executed. You need to add a call to build_archive() below the function definition and then you will start seeing output.
For example:
import psycopg2
psycopg2.autocommit = True
def build_archive(db1):
db1 = psycopg2.connect(database='postgres', user='operator',
password='1234', host='localhost', port='2280')
cursor = db1.cursor()
sql = """CREATE SCHEMA app_tools AUTHORIZATION operator;"""
cursor.execute(sql)
build_archive() # Add this call to build_archive()
To learn more about how to use functions in Python read here.
I am trying to create a login function. But it only works ones. Ex- When i give a wrong userid and password I got correct error massage that "Could't login" after canceling that message and giving correct userid and password then I get "pymysql.err.Error: Already closed" below are the sample code.
import pymysql
# Connect to the database
connection = pymysql.connect(host='localhost',
user='root',
password='',
db='python_code',
charset='utf8mb4',
cursorclass=pymysql.cursors.DictCursor)
class LoginModel:
def check_user(self, data):
try:
with connection.cursor() as cursor:
# Read a single record
sql = "SELECT `username` FROM `users` WHERE `username`=%s"
cursor.execute(sql, (data.username))
user = cursor.fetchone()
print(user)
if user:
if (user, data.password):
return user
else:
return False
else:
return False
finally:
connection.close()
You have a mismatch with respect to the number of times you're creating the connection (once) and the number of times you're closing the connection (once per login attempt).
One fix would be to move your:
connection = pymysql.connect(host='localhost',
user='root',
password='',
db='python_code',
charset='utf8mb4',
cursorclass=pymysql.cursors.DictCursor)
into your def check__user(). It would work because you'd create and close the connection on each invocation (as others have pointed out, the finally clause always gets executed.)
That's not a great design because getting database connections tends to be relatively expensive. So keeping the connection creating outside of the method is preferred.... which means you must remove the connection.close() within the method.
I think you're mixing up connection.close() with cursor.close(). You want to do the latter, not the former. In your example you don't have to explicitly close the cursor because that happens automatically with your with connection.cursor() as cursor: line.
Change finally to except, or remove the try block completely.
This is the culprit code:
finally:
connection.close()
Per the docs:
"A finally clause is always executed before leaving the try statement, whether an exception has occurred or not"
From: https://docs.python.org/2/tutorial/errors.html
You didn't describe alternative behavior for what you would like to see happen instead of this, but my answer addresses the crux of your question.
Had the same issue. The "Finally clause is needed for Postgres with the psycopg2 driver, if used with context manager (with clause), it close the cursor but not the connection. The same does not apply with Pymysql.
This link contains shows the database I've created in the mysql workbench and the connection I have established in the code but the database is unknown for some reason. Is there a step I've missed?
http://gyazo.com/d995c4da99043da43bfbd057a0a839c7
__author__ = 'avi'
from TwitterSearch import *
import json
twtsearch = TwitterSearch(
consumer_key='PXTUrlRfgC1zSTsAPU9z6EHtD',
consumer_secret='qM9F4FVj1qLFc6f795r96DQPNAJO8hkbWy4PXWYLfQcYyNGY7D',
access_token='2943116292-wVHEjbfjX7OFqaOURBqim5o7Vs6lZyjxsoto8nD',
access_token_secret='CJAppSRY9TZ5cwYTABZhH2YTd0rm5IzBDqPder6v4qLBA'
)
twtsearchorder = TwitterSearchOrder()
twtsearchorder.set_keywords(['iphone6'])
twtsearchorder.set_language('en')
twtsearchorder.set_include_entities(True)
tweet_limit=50
parsed_tweets= {}
table="twtinfo"
import MySQLdb as mdb
con = mdb.connect('localhost', 'root','root','tweetinfo')
cur=con.cursor()
for tweet in twtsearch.search_tweets_iterable(twtsearchorder):
if tweet_limit > 0 :
parsed_tweets['name'] = tweet['user']['screen_name']
parsed_tweets['content'] = tweet['text']
parsed_tweets['user_id'] = tweet['user']['id']
parsed_tweets['fav_count'] = tweet['favorite_count']
parsed_tweets['location'] = tweet['user']['location']
parsed_tweets['retweet_count'] = tweet['retweet_count']
placeholders= ', '.join(['%s'] *len(parsed_tweets))
columns = ', '.join(parsed_tweets.keys())
sql="INSERT into %s ( %s ) VALUES ( %s )" % (table, columns, placeholders)
cur.execute(sql,parsed_tweets.values())
tweet_limit -= 1
The MySQL process is complaining about the database you are trying to access, namely tweetinfo isn't existing. MySQL error 1049 is usually an indication of having to forgot to select a database, but you did as forth argument to mdb.connect()
Possible errors could be:
That you have several MySQL processes running, with the one with the proper database not being on the default MySQL port.
That somehow your database GUI application hasn't actually submitted your database and table to the MySQL process.
That MySQL isn't running? You would probably get a different error message for that, but it could be an idea to make sure it is just in case.
Just to check if your tables exists and that your database is in place, open a terminal and write the following commands:
mysql -u root -proot
use tweetinfo;
show create table twtinfo;
Another thing to try could be to ask the MySQL process about which database it thinks you are using. Try adding something like the following to your code:
cur.execute("SELECT DATABASE() FROM DUAL;")
print("Database is: %s.", cur.fetchone()[0])
I'm not a python programmer, so I'm not entirely confident that will work without some adjustments.
If none of this gave you a good lead, I'm not quite sure what's wrong.
The purpose is to check if the email already exists in the database utilizing python and MySQLdb. I am using the variable mail to store the e-mail. The MySQL form is email. I have the code below:
if cursor.execute("select count(*) from registrants where email = " + "'"email2"'") == 0:
print "it doesn't exist!"
What is wrong with this statement or how can I go about doing this?
I hardly know where to start.
Just typing a string of SQL into a Python program doesn't somehow query the database. You actually have to open a database connection, instantiate a cursor, use that cursor to run the SQL, and fetch the result. All this is explained in the MySQLdb documentation.
Once you've done that, you'll still need to actually pass the email parameter from your form to the SQL statement, which you're not doing either.
well that won't work because that's just the mysql query string. You have to execute this query using a mysql client receive the results and the test. Using pymysql would be something like this:
import pymysql
connection = pymysql.connect(host,user,password,database)
cursor = connection.cursor()
cursor.execute("select count(*) from registrants where email = ?") #you need to replace the ? with some actual value or the query will fail
result = cur.fetchone()
if result[0]==0:
print "E-mail does not exist!"