this code below runs just fine, but i want to separate this code into function (this is my first time using MySQLdb) ,
import MySQLdb
# Open database connection
db = MySQLdb.connect("localhost","user_name","pass","db_name" )
cursor = db.cursor()
sql = "SELECT activity_log.datetime FROM activity_log"
cursor.execute(sql)
date_data = cursor.fetchall()
for content in date_data:
print content
# disconnect from server
db.close()
Question: how could I create one database connection and use it to multiple functions, this is what i've wrote so far (doesn't work):
import MySQLdb
class DB():
def __init__(self):
db = MySQLdb.connect("locahost", "user_name", "pass", "db_name")
self.cur = db.cursor()
def time_statistic(self):
sql = "SELECT activity_log.datetime FROM activity_log"
self.cur.execute(sql)
self.date_data = self.cursor.fetchone()
for content in self.date_data:
print content
def test1(self):
pass
if __name__ == '__main__':
db = DB.connect("db_name" )
db.time_statistic(self)
db.test1(self)
db.close()
You need to pass the arguments to init to make sure that the class connects to the right DB.
import MySQLdb
class DB():
def __init__(self, server, user, password, db_name):
db = MySQLdb.connect(server, user, password, db_name)
self.cur = db.cursor()
def time_statistic(self):
sql = "SELECT activity_log.datetime FROM activity_log"
self.cur.execute(sql)
self.date_data = self.cursor.fetchone()
for content in self.date_data:
print content
def test1(self):
pass
if __name__ == '__main__':
db = DB(<server>, <user>, <password>, <db_name>)
db.time_statistic()
db.test1()
Replace the arguments in <> with actual values you need to connect to the db. You may also want to add some error handling in the above code.
Related
I am currently creating a program using SQLite3. While entries can be added to this database, I cannot seem to be able to delete them.
import database
db_actions = database.DatabaseActions()
def set_delete_student_parameters():
del_student_number = delete_number_enter
DeleteStudent(del_student_number)
def DeleteStudent(del_student_number):
db_actions.delete_student(del_student_number)
import sqlite3
my_conn = sqlite3.connect('general_db.db')
print("Connected to database successfully")
class DatabaseActions:
def __init__(self):
self.db = sqlite3.connect('general_db.db') # Open database connection here
self.setup_tables()
def delete_student(self, student_number):
cursor = self.db.cursor()
sql = "DELETE FROM Students WHERE StudentNumber=?"
cursor.execute(sql, [str(student_number)])
self.db.commit()
Here it is class with one of it's methods running when class is initializing:
class StatCollector:
def __init__(self, poll_stat) -> None:
self.polls = self.__get_polls()
def __get_polls(self) -> Dict[str, Poll]:
with pyodbc.connect(MSSQL_CONNECTION_PARAMS) as cnxn:
polls = dict()
cursor = cnxn.cursor()
query = self.poll_stat.poll_ids_query_getter()
cursor.execute(query, self.poll_stat.products_block)
for poll in map(Poll._make, cursor.fetchall()):
polls[poll.poll_id] = poll
return polls
I want to test other methods of this class and my first goal is to fill self.polls with initial values with no real connection to db and using __get_polls method. My try:
#patch("pyodbc.connect")
class testStatCollector(unittest.TestCase):
def test_initial_values_setted(self, mock_connect):
cursor = MagicMock(name="my_cursor")
cursor.fetchall.return_value = [("2", "А", "B")]
cnxn = MagicMock(name="my_cnxn_mfk")
cnxn.cursor.return_value = cursor
mock_connect.return_value.__enter__ = cnxn
self.test_class = PollsStatCollector(IVR)
self.assertEqual(
self.test_class.polls, {"2": Poll("2", "A", "B")}
)
self.assertIsInstance(self.test_class.period_start_time, datetime)
But self.polls are empty after execution. I got:
AssertionError: {} != {'2': Poll(poll_id='2', product='A', products_block='B')}
and I see in debug, that cnxn name = my_cnxn_mfk when __get_polls executing, but then cursor with default name = <MagicMock name='my_cnxn_mfk().cursor()' id='1883689785424'>.So i guess that i make mistake in this part cnxn.cursor.return_value = cursor, but i dont know how to fix it.
Mistake was here:
mock_connect.return_value.__enter__ = cnxn
Should be replaced with
mock_connect.return_value.__enter__.return_value = cnxn
I'm learning python since last few weeks. For better learning, I decided to work on some project. So here is my Class for MySQL connection and demo example as well. Can you please tell me. What other improvement can be possible for following code?
Structure?
What else I can do to optimize code?
And Please forgive. If I'm doing some silly mistakes in code. (I'm learning)
#!/usr/bin/python
import pymysql
# select (table, parameter)
# insert (table, data)
# update (table, id, data)
# delete (table, id)
class MySQL:
def __init__(self):
self.sort_by = ""
self.order = ""
# initiate database connection.
self.connection = pymysql.connect(host='localhost',
user='root',
password='',
db='sherlock',
charset='utf8mb4')
self.cursor = self.connection.cursor(pymysql.cursors.DictCursor)
# this function is for selecting any feild on any table.(feilds veriable is optinal)
def select(self, table, *feilds):
flds = "" #differnt name for feilds veriable.
if not feilds:
flds = '*'
else:
for f in feilds:
if not flds:
flds = f
else:
flds += ",`%s`" % f
sql = "SELECT %s FROM `%s` " % (flds, table)
if self.sort_by:
sql = sql +"order by "+ str(self.sort_by) +" "+ str(self.order)
print sql
self.cursor.execute(sql)
result = self.cursor.fetchall()
return result
# This function is for data sorting for Mysql; but optinal.
# example : SELECT * FROM `users` order by id asc
def order_by(self, sort_by="", order="", *args, **kwargs):
self.sort_by = sort_by
self.order = order
# this function is for closing Mysql connection
def close(self):
self.connection.close()
########### END OF MySQL CLASS #############
sql = MySQL()
# sql.order_by function should be called before the sql.select() function.
sql.order_by("email")
# this will select all the feilds from `users` table.
# you can specify whichever feilds you want to return. like : sql.select("users", "id, email")
result = sql.select("users", "password")
for email in result:
print email["password"]
sql.close()
I have a small problem with this class which handle my DB. It still saying:
cursor.execute(sql)
ValueError: operation parameter must be str
I tried lots of things but nothing work as i want. I looked over https://docs.python.org/3.4/library/sqlite3.html and i'm sure i do the same things.
import sqlite3
class Database():
def __init__(self):
try:
self.db = sqlite3.connect('../database.sqlite')
self.cur = self.db.cursor()
self.cur.execute('pragma foreign_keys="1"')
except sqlite3.Error as e:
raise e
def select(self,sql):
cursor = self.db.cursor()
cursor.execute(sql)
records = cursor.fetchall()
cursor.close()
return records
def insert(self,sql):
cursor = self.db.cursor()
cursor.execute(sql)
newID = cursor.lastrowid
self.db.commit()
cursor.close()
return newID
def execute(self,sql):
""" execute any SQL statement but no return value given """
cursor = self.db.cursor()
cursor.execute(sql)
self.db.commit()
cursor.close()
if __name__ == '__main__':
db = Database()
#sql = "SELECT skuref, titre_prod FROM product"
t = ("888888",)
sql= "UPDATE product SET created = 1 WHERE skuref = ?", t
db.execute(sql)
If someone can help me it would be grateful.Later i wanted to pass something like this in the main program inside a for loop
lastpost = record[0]
if created = True
sql = "UPDATE product SET created = 1 WHERE skuref = ?",(lastpost,)
db.execute(sql)
sql is a tuple containing SQL statement and the parameters.
Change as following, so that sql and parameters are passed separately, instead of being passed as a tuple:
def execute(self, sql):
""" execute any SQL statement but no return value given """
cursor = self.db.cursor()
cursor.execute(*sql) # <------
self.db.commit()
cursor.close()
With your statement
sql = "UPDATE product SET created = 1 WHERE skuref = ?",(lastpost,)
you have created a tupel like
("UPDATE product SET created = 1 WHERE skuref = ?", (lastpost,))
You have to give the arguments as parameters to the execute() function.
Also your if statement is bad: no :, = instead of == and the whole check for True is no nesesary.
Try this:
lastpost = record[0]
if created:
sql = "UPDATE product SET created = 1 WHERE skuref = ?"
db.execute(sql, lastpost)
I'm new to python and I'm trying to make this work. I'm using Python 2.7 and PostgreSQL 9.3:
#! F:\Python2.7.6\python
import psycopg2
class Database:
host = "192.168.56.101"
user = "testuser"
passwd = "passwd"
db = "test"
def __init__(self):
self.connection = psycopg2.connect( host = self.host,
user = self.user,
password = self.passwd,
dbname = self.db )
self.cursor = self.connection.cursor
def query(self, q):
cursor = self.cursor
cursor.execute(q)
return cursor.fetchall()
def __del__(self):
self.connection.close()
if __name__ == "__main__":
db = Database()
q = "DELETE FROM testschema.test"
db.query(q)
However I am getting an error "AttributeError: 'builtin_function_or_method' object has no attribute 'execute'". I figure I should put something like self.execute = something in the Database class, but I can't figure it out what exactly I need to put there. Any suggestions?
You are missing the parenthesis at the end
self.cursor = self.connection.cursor()
or
cursor = self.cursor()
But not both