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Python: No of rows are always 9 and does not return affected rows count after UPDATE query

This is not something complicated but not sure why is it not working
import mysql.connector
def get_connection(host, user, password, db_name):
connection = None
try:
connection = mysql.connector.connect(
host=host,
user=user,
use_unicode=True,
password=password,
database=db_name
)
connection.set_charset_collation('utf8')
print('Connected')
except Exception as ex:
print(str(ex))
finally:
return connection
with connection.cursor() as cursor:
sql = 'UPDATE {} set underlying_price=9'.format(table_name)
cursor.execute(sql)
connection.commit()
print('No of Rows Updated ...', cursor.rowcount)
It always returns 0 no matter what. The same query shows correct count on TablePlus
MysQL API provides this method but I do not know how to call it as calling against connection variable gives error

I am not sure why your code does not work. But i am using pymysql, and it works
import os
import pandas as pd
from types import SimpleNamespace
from sqlalchemy import create_engine
import pymysql
PARAM = SimpleNamespace()
PARAM.DB_user='yourname'
PARAM.DB_password='yourpassword'
PARAM.DB_name ='world'
PARAM.DB_ip = 'localhost'
def get_DB_engine_con(PARAM):
DB_name = PARAM.DB_name
DB_ip = PARAM.DB_ip
DB_user = PARAM.DB_user
DB_password = PARAM.DB_password
## engine = create_engine("mysql+pymysql://{user}:{pw}#{ip}/{db}".format(user=DB_user,pw=DB_password,db=DB_name,ip=DB_ip))
conn = pymysql.connect(host=DB_ip, user=DB_user,passwd=DB_password,db=DB_name)
cur = conn.cursor()
return cur, conn ## , engine
cur, conn = get_DB_engine_con(PARAM)
and my data
if i run the code
table_name='ct2'
sql = "UPDATE {} set CountryCode='NL' ".format(table_name)
cur.execute(sql)
conn.commit()
print('No of Rows Updated ...', cur.rowcount)
the result No of Rows Updated ... 10 is printed. and the NLD is changed to NL
If using mysql.connector
import mysql.connector
connection = mysql.connector.connect(
host=PARAM.DB_ip,
user=PARAM.DB_user,
use_unicode=True,
password=PARAM.DB_password,
database=PARAM.DB_name
)
cur = connection.cursor()
table_name='ct2'
sql = "UPDATE {} set CountryCode='NL2' ".format(table_name)
cur.execute(sql)
print('No of Rows Updated ...', cur.rowcount)
connection.commit()
it still works
and the country code is updated to NL2 and No of Rows Updated ... 10 is printed. The second time i run then No of Rows Updated ... 0 is printed.
Not sure why it does not work on your machine.

impyla - as_pandas - empty dataframe

I have a simple impyla code, and I would like to create a pandas dataFrame from my cursor. My code is running but my dataframe is always an empty dataframe.
If I run my query directly on impala, the result is not empty. This is how my code looks like:
from impala.dbapi import connect
from impala.util import as_pandas
conn = connect(host='impala_server', port=21051,
user='user' , password='pass',
use_ssl=True,
auth_mechanism='PLAIN')
cursor = conn.cursor()
cursor.execute("SELECT * FROM TABLE")
results = cursor.fetchall()
df = as_pandas(cursor)
print(df.head())
Help me please, what am I doing wrong?

Just remove:
results = cursor.fetchall()
from your code. It should work.

'results = cursor.fetchall() ' delete this line and it will be ok.
from impala.dbapi import connect
from impala.util import as_pandas
conn = connect(host='****.com', port=****, database='****')
cursor = conn.cursor()
cursor.execute('select * from table limit 10')
df = as_pandas(cursor)
df.head()
I run the code above, and it run well.

Python script to read single value from MS SQL Server 2008

I just need to read a single value from an MS SQL Server 2008 connection, but I'm not sure how to do this. Here is the code
import pyodbc
querystring = """SELECT USER_NAME
FROM sem6.sem_computer, [sem6].[V_SEM_COMPUTER], sem6.IDENTITY_MAP, sem6.SEM_CLIENT
WHERE [sem6].[V_SEM_COMPUTER].COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
AND sem6.SEM_CLIENT.GROUP_ID = IDENTITY_MAP.ID
AND sem6.SEM_CLIENT.COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
AND [IP_ADDR1_TEXT] = '10.10.10.10'
"""
con = pyodbc.connect('DRIVER={SQL Server};SERVER=10.10.10.100;DATABASE=databasename;UID=username;PWD=password')
cur = con.cursor()
cur.execute(querystring)
con.commit()
con.close()

You need to fetch the result after executing the query. See PEP 249 for how the dbapi exposes this.
In your case, username = cur.fetchone()[0] will work.

According to python's DB-API, you need to do fetchone to retrieve the first row:
import pyodbc
querystring = """SELECT USER_NAME
FROM sem6.sem_computer, [sem6].[V_SEM_COMPUTER], sem6.IDENTITY_MAP, sem6.SEM_CLIENT
WHERE [sem6].[V_SEM_COMPUTER].COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
AND sem6.SEM_CLIENT.GROUP_ID = IDENTITY_MAP.ID
AND sem6.SEM_CLIENT.COMPUTER_ID = SEM_COMPUTER.COMPUTER_ID
AND [IP_ADDR1_TEXT] = '10.10.10.10'
"""
con = pyodbc.connect('DRIVER={SQL Server};SERVER=10.10.10.100;DATABASE=databasename;UID=username;PWD=password')
cur = con.cursor()
cur.execute(querystring)
row = cur.fetchone()
print(row[0])
con.close()

Python equivalent of PHP mysql_fetch_array

I would like to fetch an array in MySQL. Can someone please tell me how to use Python using MySQLdb to do so?
For example, this is what I would like to do in Python:
<?php
require_once('Config.php');
$q = mysql_query("SELECT * FROM users WHERE firstname = 'namehere'");
$data = mysql_fetch_array($q);
echo $data['lastname'];
?>
Thanks.

In python you have dictionary=True, I have tested in python3. This returns directory which is much similar to associative array in php.
eg.
import mysql.connector
cnx = mysql.connector.connect(user='root', password='',host='127.0.0.1',database='test1')
cursor = cnx.cursor(dictionary=True)
sql= ("SELECT * FROM `users` WHERE id>0")
cursor.execute(sql)
results = cursor.fetchall()
print(results)

You can use this (dictionary=True):
import mysql.connector
db = mysql.connector.connect(user='root', password='',host='127.0.0.1', database='test1')
cursor = db.cursor(dictionary=True)
cursor.execute("SELECT * FROM table")
for row in cursor:
print(row['column'])

Install MySQLdb (the drivers for MySQL for Python). Type pip install mysql-python
Read up on the Python DB API, which is the standard way to access databases in Python.
Then, try this:
>>> import MySQLdb
>>> connection = MySQLdb.connect(database='test')
>>> cursor = connection.cursor()
>>> cursor.execute('SELECT * FROM users WHERE firstname = %s',('somename',))
>>> results = cursor.fetchall()
>>> for i in results:
print i

I would use SQLAlchemy. Something like this would do the trick:
engine = create_engine('mysql://username:password#host:port/database')
connection = engine.connect()
result = connection.execute("select username from users")
for row in result:
print "username:", row['username']
connection.close()

Try:
import MySQLdb
connection = MySQLdb.connect(host="localhost", # your host
user="root", # username
passwd="password", # password
db="frateData") # name of the database)
cursor = connection.cursor(MySQLdb.cursors.DictCursor)
cursor.execute('SELECT * FROM users WHERE firstname = %s',['namehere'])
data = cursor.fetchall()
print data['lastname']
Please note that by initiating your cursor by passing the following parameter: "MySQLdb.cursors.DictCursor"
a list instead of an array is returned so you can reference the data with their key name, which in your case in lastname.

Python using PRE-FETCH on Oracle 10

import cx_Oracle
import wx
print "Start..." + str(wx.Now())
base = cx_Oracle.makedsn('xxx', port, 'yyyy')
connection = cx_Oracle.connect(user name, password, base)
cursor = connection.cursor()
cursor.execute('select data from t_table')
li_row = cursor.fetchall()
data = []
for row in li_row:
data.append(row[0])
cursor.close()
connection.close()
print "End..." + str(wx.Now())
print "DONE!!!"
Is there a way to integrate pre-fetch in this program? My goal is to get data from database as quick as possible.

Fetching 10000 rows...
cursor.arraysize = 10000