how I connect local database?

Question

that is my code :

from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import mysql.connector
import mysql.connector.cursor
from mysql.connector import errorcode
import sys
import os
from os import path
from PyQt5.uic import loadUiType
FORM_CLASS,_ = loadUiType(path.join(path.dirname(__file__),"mainwindow.ui"))
class Main(QMainWindow,FORM_CLASS):
 def __init__(self,parent=None):
 super(Main,self).__init__(parent)
 QMainWindow.__init__(self)
 self.setupUi(self)
 self.InitUI()
 self.Handel_buttons()
 self.Handel_db_connections()
 def InitUI(self):
 ## changes in the run time
 pass
 def Handel_buttons(self):
 ## all buttons in the app
 self.pushButton.clicked.connect(self.add_mahmoud_friends)
 self.pushButton_3.clicked.connect(self.update_mahmoud_friends)
 self.pushButton_2.clicked.connect(self.delete_mahmoud_friends)
 def Handel_db_connections(self):
 try:
 conn = mysql.connector.connect(host='localhost',
 database='mydb',
 user='root',
 password='*******',
 use_pure=True) # use_pure is set to true
 if conn.is_connected():
 db_Info = conn.get_server_info()
 print("Connected to MySQL database using C extension... MySQL Server version on ", db_Info)
 self.c = conn.cursor()
 except errorcode as e:
 print("Error while connecting to MySQL using C extension", e)
 finally:
 # closing database connection.
 if (conn.is_connected()):
 print("connection is closed")
 ####################################################
 ## mahmoud info
 def add_mahmoud_friends(self):
 mth_friends = self.lineEdit.text()
 self.c.execute('''INSERT INTO mtth (mth_friends) values (%s)''', (mth_friends))
 print("done")
 def update_mahmoud_friends(self):
 pass
 def delete_mahmoud_friends(self):
 pass
def main():
 app= QApplication(sys.argv)
 window =Main()
 window.show()
 app.exec_()
if __name__ == '__main__':
 main()

when I used that code connection is established but it causes that error on inserting information into SQL Database made by mysql workbench the error is:

Connected to MySQL database using C extension... MySQL Server version on 8.0.12
connection is closed
Traceback (most recent call last):
 File "/Users/mahmoudtarek/Desktop/mth1/index.py", line 60, in add_mahmoud_friends
 self.c.execute('''INSERT INTO mtth (mth_friends) values (%s)''', (mth_friends))
 File "/Users/mahmoudtarek/PycharmProjects/untitled/venv/lib/python3.7/site-packages/mysql/connector/cursor.py", line 533, in execute
 if not self._connection:
ReferenceError: weakly-referenced object no longer exists
Process finished with exit code 134 (interrupted by signal 6: SIGABRT)

Answer 1

What you have to save is the connector, on the other hand the interaction with the database can bring problems so you must use try-except, you must also call commit() to execute the commands.

import sys
import os
from PyQt5 import QtCore, QtGui, QtWidgets, uic
import mysql.connector
from mysql.connector import errorcode
FORM_CLASS, _ = uic.loadUiType(os.path.join(os.path.dirname(__file__),"mainwindow.ui"))
class Main(QtWidgets.QMainWindow, FORM_CLASS):
 def __init__(self,parent=None):
 super(Main,self).__init__(parent)
 self.setupUi(self)
 self.InitUI()
 self.conn = None
 self.handle_buttons()
 self.handle_db_connections()
 def InitUI(self):
 ## changes in the run time
 pass
 def handle_buttons(self):
 ## all buttons in the app
 self.pushButton.clicked.connect(self.add_mahmoud_friends)
 self.pushButton_3.clicked.connect(self.update_mahmoud_friends)
 self.pushButton_2.clicked.connect(self.delete_mahmoud_friends)
 def handle_db_connections(self):
 try:
 self.conn = mysql.connector.connect(
 host='localhost',
 database='mydb',
 user='root',
 password='*******',
 use_pure=True) # use_pure is set to true
 if self.conn.is_connected():
 db_Info = self.conn.get_server_info()
 print("Connected to MySQL database using C extension... MySQL Server version on ", db_Info)
 except mysql.connector.Error as err:
 print("Error while connecting to MySQL using C extension", err)
 def add_mahmoud_friends(self):
 mth_friends = self.lineEdit.text()
 if self.conn:
 c = self.conn.cursor()
 try:
 c.execute('''INSERT INTO mtth (mth_friends) values (%s)''', (mth_friends,))
 self.conn.commit()
 except mysql.connector.Error as err:
 print("Error: ", err)
 def update_mahmoud_friends(self):
 pass
 def delete_mahmoud_friends(self):
 pass
 def closeEvent(self, event):
 if self.conn:
 self.conn.close()
 super(Main, self).closeEvent(event)
def main():
 app= QtWidgets.QApplication(sys.argv)
 window =Main()
 window.show()
 app.exec_()
if __name__ == '__main__':
 main()

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