Question

that is my app and I used search button to edit information easily我在python中使用该代码向本地数据库添加，删除，更新信息...。在添加信息中运行良好，但是当我使用update时，数据库中的所有信息或行都变为相同。此外，在删除所有数据时，可能是由于使用一个搜索栏删除了所有要删除或编辑的数据

这是我的代码：

import sys
import os
import time

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__),"mahmoudtarek.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)
        self.pushButton_6.clicked.connect(self.search_mahmoud_friends)


    def handle_db_connections(self):
        try:
            self.conn = mysql.connector.connect(
                host='127.0.0.1',
                database='mydb',
                user='root',
                password='134668691011',
                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()
        mth_search = self.lineEdit_4.text()
        if self.conn:
            c = self.conn.cursor()
            try:
                c.execute('''INSERT INTO ahmed (mth_friends,mth_search) values (%s,%s)''', (mth_friends,mth_search))
                self.conn.commit()
                self.lineEdit.setText('')
                self.lineEdit_4.setText('')
                self.statusBar.showMessage('ok mahmoud')


            except mysql.connector.Error as err:
                print("Error: ", err)

    def update_mahmoud_friends(self):
        mth_friends = self.lineEdit.text()
        mth_search = self.lineEdit_4.text()
        if self.conn:
            c = self.conn.cursor()
            try:
                c.execute('''UPDATE ahmed SET mth_friends = %s,mth_search = %s''', (mth_friends, mth_search))
                self.conn.commit()
                self.lineEdit.setText('')
                self.lineEdit_4.setText('')
                self.statusBar.showMessage('ok mahmoud')
                self.lineEdit_3.setText('')


            except mysql.connector.Error as err:
                print("Error: ", err)

    def delete_mahmoud_friends(self):
        c = self.conn.cursor()
        sql = '''DELETE FROM ahmed WHERE mth_search = %s'''
        mth_search = self.lineEdit_3.text()
        c.execute(sql, [(mth_search)])
        self.conn.commit()
        self.statusBar.showMessage("ok")
        self.lineEdit.setText('')
        self.lineEdit_4.setText('')
        self.lineEdit_3.setText('')


    def search_mahmoud_friends(self):
        if self.conn:
            c = self.conn.cursor()

            try:

                sql = '''SELECT * FROM ahmed WHERE mth_search = %s'''
                mth_search = self.lineEdit_3.text()
                c.execute(sql, [(mth_search)])
                data = c.fetchall()
                for row in data :
                    print(row)
                    self.lineEdit.setText(str(row[1]))
                    self.lineEdit_4.setText(str(row[2]))

            except mysql.connector.Error as err:
              print("Error: ", err)

    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()

我仍然是个初学者，因此需要帮助。如果有人知道问题所在，请给我写正确的代码。当我搜索过多...最后感谢您

Answer 1

UPDATE时，您需要添加一个条件，否则表中的每一行都将使用这些值进行更新。

在您的代码中：

c.execute('''UPDATE ahmed SET mth_friends = %s,mth_search = %s''', (mth_friends, mth_search))

应该有这样的条件：

c.execute('''UPDATE ahmed SET mth_friends = %s,mth_search = %s WHERE {ADD CONDITION HERE}''', (mth_friends, mth_search))

如果要更新或删除单行，则希望条件匹配主键或唯一键列。使用涉及任何其他类型列的条件将更新或删除与该条件匹配的所有行。（感谢Raymond Nijland）

如何只删除或编辑sql表中的一行？

1 个答案: