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How do I display the records fetched from my database to my listwidget?

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  • A Abhishek_98

    @SGaist I prefer python over Qt's SQL classes, as I am currently undergoing my python training classes and moreover I am much more comfortable with python rather than Qt's exclusive SQL language.

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by jsulm
    #7

    @Abhishek_98 said in How do I display the records fetched from my database to my listwidget?:

    Qt's exclusive SQL language

    there is no such thing. Qt simply provides APIs to access SQL databases, but SQL syntax is same and depends on used SQL database, not Qt.

    https://forum.qt.io/topic/113070/qt-code-of-conduct

    1 Reply Last reply
    0
    • A Offline
      A Offline
      Abhishek_98
      wrote on last edited by
      #8

      can anyone please just tell my why the items aren't being displayed in the listwidget? Is there something wrong with the code?

      jsulmJ JonBJ 2 Replies Last reply
      0
      • A Abhishek_98

        can anyone please just tell my why the items aren't being displayed in the listwidget? Is there something wrong with the code?

        jsulmJ Offline
        jsulmJ Offline
        jsulm
        Lifetime Qt Champion
        wrote on last edited by jsulm
        #9

        @Abhishek_98 Did you check the length of rec?
        "The records get fetched (I've tried fetching on cmd and it works)" - it may work in cmd but not in your app.
        Best would be to debug to see what happens.

        https://forum.qt.io/topic/113070/qt-code-of-conduct

        1 Reply Last reply
        1
        • A Abhishek_98

          can anyone please just tell my why the items aren't being displayed in the listwidget? Is there something wrong with the code?

          JonBJ Offline
          JonBJ Offline
          JonB
          wrote on last edited by JonB
          #10

          @Abhishek_98
          Do you not get items added to the list widget, or do you get blank items? What is item.text() each time?

          rec=cur.fetchall()
          

          Does that not return a list of rows?

           for item in rec:
          

          Then item would be a row, not a column value in a row. Even if it's a result set with just one row of one column. If item is a row, what is item.text()?

          Python's print(rec) can print what it likes, probably str(rec).

          1 Reply Last reply
          2
          • Kent-DorfmanK Offline
            Kent-DorfmanK Offline
            Kent-Dorfman
            wrote on last edited by Kent-Dorfman
            #11

            two comments:

            1. why do you do cur=db.cursor() twice?

            2. your problem may be related to the format that the data is returned in rec (assuming rec actually has something in it). What does the print(rec) actually print out?

            3)skip what I wrote above...as JonB ppointed out... cur.fetchall() will return a LIST of records, and within each record will be a LIST of fields. You are not parsing your SQL response properly.

            1 Reply Last reply
            2
            • T Offline
              T Offline
              Tejaswini_14
              wrote on last edited by
              #12

              I have the same problem...Please help if you have the solution

              SGaistS 1 Reply Last reply
              0
              • T Tejaswini_14

                I have the same problem...Please help if you have the solution

                SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #13

                @Tejaswini_14 hi and welcome to devnet,

                Did you follow what people already suggested/asked to do on this thread ?

                Interested in AI ? www.idiap.ch
                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                1 Reply Last reply
                0
                • T Offline
                  T Offline
                  Tejaswini_14
                  wrote on last edited by
                  #14

                  Actually I am at the beginning level in Python and I have made some changes to my code but whenever I click on QRadioButton it shows "Python has stopped working".

                  JonBJ 1 Reply Last reply
                  0
                  • T Tejaswini_14

                    Actually I am at the beginning level in Python and I have made some changes to my code but whenever I click on QRadioButton it shows "Python has stopped working".

                    JonBJ Offline
                    JonBJ Offline
                    JonB
                    wrote on last edited by
                    #15

                    @Tejaswini_14
                    Sorry, but nobody is going to be able to help you from that description of a problem.

                    1 Reply Last reply
                    0
                    • T Offline
                      T Offline
                      Tejaswini_14
                      wrote on last edited by
                      #16

                      Here is my code

                      from PyQt5 import QtCore, QtGui, QtWidgets
                      import sqlite3
                      db=sqlite3.connect("fantcktdb.db")
                      cur=db.cursor()
                      
                      class Ui_MainWindow(object):
                          def setupUi(self, MainWindow):
                              MainWindow.setObjectName("MainWindow")
                              MainWindow.resize(800, 600)
                              self.centralwidget = QtWidgets.QWidget(MainWindow)
                              self.centralwidget.setObjectName("centralwidget")
                              self.gridLayout = QtWidgets.QGridLayout(self.centralwidget)
                              self.gridLayout.setObjectName("gridLayout")
                              self.frame = QtWidgets.QFrame(self.centralwidget)
                              self.frame.setFrameShape(QtWidgets.QFrame.StyledPanel)
                              self.frame.setFrameShadow(QtWidgets.QFrame.Raised)
                              self.frame.setObjectName("frame")
                              self.gridLayout_2 = QtWidgets.QGridLayout(self.frame)
                              self.gridLayout_2.setObjectName("gridLayout_2")
                              self.verticalLayout = QtWidgets.QVBoxLayout()
                              self.verticalLayout.setObjectName("verticalLayout")
                              self.wkRadio = QtWidgets.QRadioButton(self.frame)
                              self.wkRadio.setObjectName("wkRadio")
                              self.buttonGroup = QtWidgets.QButtonGroup(MainWindow)
                              self.buttonGroup.setObjectName("buttonGroup")
                              self.buttonGroup.addButton(self.wkRadio)
                              self.verticalLayout.addWidget(self.wkRadio)
                              self.arRadio = QtWidgets.QRadioButton(self.frame)
                              self.arRadio.setObjectName("arRadio")
                              self.buttonGroup.addButton(self.arRadio)
                              self.verticalLayout.addWidget(self.arRadio)
                              self.bowRadio = QtWidgets.QRadioButton(self.frame)
                              self.bowRadio.setObjectName("bowRadio")
                              self.buttonGroup.addButton(self.bowRadio)
                              self.verticalLayout.addWidget(self.bowRadio)
                              self.batRadio = QtWidgets.QRadioButton(self.frame)
                              self.batRadio.setObjectName("batRadio")
                              self.buttonGroup.addButton(self.batRadio)
                              self.verticalLayout.addWidget(self.batRadio)
                              self.buttonGroup.buttonToggled.connect(self.showList)
                              self.listWidget = QtWidgets.QListWidget(self.frame)
                              self.listWidget.setObjectName("listWidget")
                              self.verticalLayout.addWidget(self.listWidget)
                              self.gridLayout_2.addLayout(self.verticalLayout, 0, 0, 1, 1)
                              self.gridLayout.addWidget(self.frame, 0, 0, 1, 1)
                              MainWindow.setCentralWidget(self.centralwidget)
                              self.menubar = QtWidgets.QMenuBar(MainWindow)
                              self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 26))
                              self.menubar.setObjectName("menubar")
                              MainWindow.setMenuBar(self.menubar)
                              self.statusbar = QtWidgets.QStatusBar(MainWindow)
                              self.statusbar.setObjectName("statusbar")
                              MainWindow.setStatusBar(self.statusbar)
                      
                              self.retranslateUi(MainWindow)
                              QtCore.QMetaObject.connectSlotsByName(MainWindow)
                      
                          def showList(self,MainWindow):
                              if (self.batRadio.isChecked()==True):
                                  cur.execute('''SELECT Player FROM stats WHERE Ctg='BAT';''')
                                  records=cur.fetchall()
                                  self.listWidget.clear()
                                  for row in records:
                                      self.listWidget.addItems(row)
                                  self.listWidget.update()
                              elif (self.bowRadio.isChecked()==True):
                                  cur.execute('''SELECT Player FROM stats WHERE Ctg='BOW';''')
                                  records=cur.fetchall()
                                  self.listWidget.clear()
                                  for row in records:
                                      self.listWidget.addItems(row)
                                  self.listWidget.update()
                              elif (self.arRadio.isChecked()==True):
                                  cur.execute('''SELECT Player FROM stats WHERE Ctg='AR';''')
                                  records=cur.fetchall()
                                  self.listWidget.clear()
                                  for row in records:
                                      self.listWidget.addItems(row)
                                  self.listWidget.update()
                              elif (self.wkRadio.isChecked()==True):
                                  cur.execute('''SELECT Player FROM stats WHERE Ctg='WK';''')
                                  records=cur.fetchall()
                                  self.listWidget.clear()
                                  for row in records:
                                      self.listWidget.addItems(row)
                                  self.listWidget.update()
                          def retranslateUi(self, MainWindow):
                              _translate = QtCore.QCoreApplication.translate
                              MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
                              self.wkRadio.setText(_translate("MainWindow", "WK"))
                              self.arRadio.setText(_translate("MainWindow", "AR"))
                              self.bowRadio.setText(_translate("MainWindow", "BOW"))
                              self.batRadio.setText(_translate("MainWindow", "BAT"))
                      
                      
                      if __name__ == "__main__":
                          import sys
                          app = QtWidgets.QApplication(sys.argv)
                          MainWindow = QtWidgets.QMainWindow()
                          ui = Ui_MainWindow()
                          ui.setupUi(MainWindow)
                          MainWindow.show()
                          sys.exit(app.exec_())
                      
                      JonBJ 1 Reply Last reply
                      0
                      • T Tejaswini_14

                        Here is my code

                        from PyQt5 import QtCore, QtGui, QtWidgets
                        import sqlite3
                        db=sqlite3.connect("fantcktdb.db")
                        cur=db.cursor()
                        
                        class Ui_MainWindow(object):
                            def setupUi(self, MainWindow):
                                MainWindow.setObjectName("MainWindow")
                                MainWindow.resize(800, 600)
                                self.centralwidget = QtWidgets.QWidget(MainWindow)
                                self.centralwidget.setObjectName("centralwidget")
                                self.gridLayout = QtWidgets.QGridLayout(self.centralwidget)
                                self.gridLayout.setObjectName("gridLayout")
                                self.frame = QtWidgets.QFrame(self.centralwidget)
                                self.frame.setFrameShape(QtWidgets.QFrame.StyledPanel)
                                self.frame.setFrameShadow(QtWidgets.QFrame.Raised)
                                self.frame.setObjectName("frame")
                                self.gridLayout_2 = QtWidgets.QGridLayout(self.frame)
                                self.gridLayout_2.setObjectName("gridLayout_2")
                                self.verticalLayout = QtWidgets.QVBoxLayout()
                                self.verticalLayout.setObjectName("verticalLayout")
                                self.wkRadio = QtWidgets.QRadioButton(self.frame)
                                self.wkRadio.setObjectName("wkRadio")
                                self.buttonGroup = QtWidgets.QButtonGroup(MainWindow)
                                self.buttonGroup.setObjectName("buttonGroup")
                                self.buttonGroup.addButton(self.wkRadio)
                                self.verticalLayout.addWidget(self.wkRadio)
                                self.arRadio = QtWidgets.QRadioButton(self.frame)
                                self.arRadio.setObjectName("arRadio")
                                self.buttonGroup.addButton(self.arRadio)
                                self.verticalLayout.addWidget(self.arRadio)
                                self.bowRadio = QtWidgets.QRadioButton(self.frame)
                                self.bowRadio.setObjectName("bowRadio")
                                self.buttonGroup.addButton(self.bowRadio)
                                self.verticalLayout.addWidget(self.bowRadio)
                                self.batRadio = QtWidgets.QRadioButton(self.frame)
                                self.batRadio.setObjectName("batRadio")
                                self.buttonGroup.addButton(self.batRadio)
                                self.verticalLayout.addWidget(self.batRadio)
                                self.buttonGroup.buttonToggled.connect(self.showList)
                                self.listWidget = QtWidgets.QListWidget(self.frame)
                                self.listWidget.setObjectName("listWidget")
                                self.verticalLayout.addWidget(self.listWidget)
                                self.gridLayout_2.addLayout(self.verticalLayout, 0, 0, 1, 1)
                                self.gridLayout.addWidget(self.frame, 0, 0, 1, 1)
                                MainWindow.setCentralWidget(self.centralwidget)
                                self.menubar = QtWidgets.QMenuBar(MainWindow)
                                self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 26))
                                self.menubar.setObjectName("menubar")
                                MainWindow.setMenuBar(self.menubar)
                                self.statusbar = QtWidgets.QStatusBar(MainWindow)
                                self.statusbar.setObjectName("statusbar")
                                MainWindow.setStatusBar(self.statusbar)
                        
                                self.retranslateUi(MainWindow)
                                QtCore.QMetaObject.connectSlotsByName(MainWindow)
                        
                            def showList(self,MainWindow):
                                if (self.batRadio.isChecked()==True):
                                    cur.execute('''SELECT Player FROM stats WHERE Ctg='BAT';''')
                                    records=cur.fetchall()
                                    self.listWidget.clear()
                                    for row in records:
                                        self.listWidget.addItems(row)
                                    self.listWidget.update()
                                elif (self.bowRadio.isChecked()==True):
                                    cur.execute('''SELECT Player FROM stats WHERE Ctg='BOW';''')
                                    records=cur.fetchall()
                                    self.listWidget.clear()
                                    for row in records:
                                        self.listWidget.addItems(row)
                                    self.listWidget.update()
                                elif (self.arRadio.isChecked()==True):
                                    cur.execute('''SELECT Player FROM stats WHERE Ctg='AR';''')
                                    records=cur.fetchall()
                                    self.listWidget.clear()
                                    for row in records:
                                        self.listWidget.addItems(row)
                                    self.listWidget.update()
                                elif (self.wkRadio.isChecked()==True):
                                    cur.execute('''SELECT Player FROM stats WHERE Ctg='WK';''')
                                    records=cur.fetchall()
                                    self.listWidget.clear()
                                    for row in records:
                                        self.listWidget.addItems(row)
                                    self.listWidget.update()
                            def retranslateUi(self, MainWindow):
                                _translate = QtCore.QCoreApplication.translate
                                MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
                                self.wkRadio.setText(_translate("MainWindow", "WK"))
                                self.arRadio.setText(_translate("MainWindow", "AR"))
                                self.bowRadio.setText(_translate("MainWindow", "BOW"))
                                self.batRadio.setText(_translate("MainWindow", "BAT"))
                        
                        
                        if __name__ == "__main__":
                            import sys
                            app = QtWidgets.QApplication(sys.argv)
                            MainWindow = QtWidgets.QMainWindow()
                            ui = Ui_MainWindow()
                            ui.setupUi(MainWindow)
                            MainWindow.show()
                            sys.exit(app.exec_())
                        
                        JonBJ Offline
                        JonBJ Offline
                        JonB
                        wrote on last edited by JonB
                        #17

                        @Tejaswini_14
                        I think you need to read carefully through the posts above. If I say so myself, you/the OP did not respond to my own reply, which I think would indicate you cannot just go for row in records::

                        @Abhishek_98
                        Do you not get items added to the list widget, or do you get blank items? What is item.text() each time?

                        rec=cur.fetchall()

                        Does that not return a list of rows?

                        for item in rec:

                        Then item would be a row, not a column value in a row. Even if it's a result set with just one row of one column. If item is a row, what is item.text()?

                        Python's print(rec) can print what it likes, probably str(rec).

                        1 Reply Last reply
                        1
                        • T Offline
                          T Offline
                          Tejaswini_14
                          wrote on last edited by
                          #18

                          I am fetching only one column which is "Player", then why should I use index values. Also I have tried to use index when I fetch all columns. e.g.

                          if (self.batRadio.isChecked()==True):
                                      bat='BAT'
                                      sql="SELECT * FROM stats WHERE Ctg='"+bat+"';"
                                      cur.execute(sql)
                                      records=cur.fetchall()
                                      for row in records:
                                          item=row[0]
                                          print(item)
                                          self.listWidget.addItem(item.text())
                          
                          JonBJ 1 Reply Last reply
                          0
                          • T Tejaswini_14

                            I am fetching only one column which is "Player", then why should I use index values. Also I have tried to use index when I fetch all columns. e.g.

                            if (self.batRadio.isChecked()==True):
                                        bat='BAT'
                                        sql="SELECT * FROM stats WHERE Ctg='"+bat+"';"
                                        cur.execute(sql)
                                        records=cur.fetchall()
                                        for row in records:
                                            item=row[0]
                                            print(item)
                                            self.listWidget.addItem(item.text())
                            
                            JonBJ Offline
                            JonBJ Offline
                            JonB
                            wrote on last edited by JonB
                            #19

                            @Tejaswini_14 said in How do I display the records fetched from my database to my listwidget?:

                            I am fetching only one column which is "Player", then why should I use index values

                            Because the fact that your particular SELECT statement is only returning one column, instead of say SELECT column1, column2, column3, does not alter cur.fetchall()'s behaviour of returning a list or rows, each of which holds a list of columns. Hence I assume you need row[0] to pick out column #0.

                            Also I have tried to use index when I fetch all columns. e.g.

                            And? You don't say what happens? You have print(item) yet you don't bother to tell us what that shows, or even if it gets hit? And I asked

                            What is item.text() each time?

                            but you don't show that, so I don't know what you actually passing in self.listWidget.addItem(item.text())?

                            1 Reply Last reply
                            1
                            • T Offline
                              T Offline
                              Tejaswini_14
                              wrote on last edited by
                              #20

                              I am getting error like this when I execute query seperately

                              Traceback (most recent call last):
                              File "C:\Python36\Scripts\FantasyCricket.py", line 17, in <module>
                              cur.execute('''SELECT * FROM stats WHERE Ctg="BAT";''')
                              sqlite3.OperationalError: no such table: stats
                              

                              Even if I have the table stats stored in database

                              mrjjM JonBJ 2 Replies Last reply
                              0
                              • T Tejaswini_14

                                I am getting error like this when I execute query seperately

                                Traceback (most recent call last):
                                File "C:\Python36\Scripts\FantasyCricket.py", line 17, in <module>
                                cur.execute('''SELECT * FROM stats WHERE Ctg="BAT";''')
                                sqlite3.OperationalError: no such table: stats
                                

                                Even if I have the table stats stored in database

                                mrjjM Offline
                                mrjjM Offline
                                mrjj
                                Lifetime Qt Champion
                                wrote on last edited by
                                #21

                                @Tejaswini_14

                                Hi
                                make very, very sure that it finds
                                "fantcktdb.db"
                                else it will create new empty one
                                so if you have yours in say your project folder, then
                                when run it might create a new one in build folder.
                                so please use full path to it to be sure it find the one you have data in.

                                T 1 Reply Last reply
                                3
                                • T Tejaswini_14

                                  I am getting error like this when I execute query seperately

                                  Traceback (most recent call last):
                                  File "C:\Python36\Scripts\FantasyCricket.py", line 17, in <module>
                                  cur.execute('''SELECT * FROM stats WHERE Ctg="BAT";''')
                                  sqlite3.OperationalError: no such table: stats
                                  

                                  Even if I have the table stats stored in database

                                  JonBJ Offline
                                  JonBJ Offline
                                  JonB
                                  wrote on last edited by JonB
                                  #22

                                  @Tejaswini_14
                                  So since you are using Python sqlite3 library calls, not Qt ones, to access your database this is a Python issue not a Qt one, and you would be better asking that in a Python/SQLite forum. It also means that adding to a QListWidget is not itself an issue.

                                  EDIT This post has crossed with @mrjj's which is quite possibly the cause. If you're not sure where the database file is being picked up, perhaps (temporarily) change your db=sqlite3.connect("fantcktdb.db") to specify the full path to the intended file location.

                                  T 1 Reply Last reply
                                  3
                                  • mrjjM mrjj

                                    @Tejaswini_14

                                    Hi
                                    make very, very sure that it finds
                                    "fantcktdb.db"
                                    else it will create new empty one
                                    so if you have yours in say your project folder, then
                                    when run it might create a new one in build folder.
                                    so please use full path to it to be sure it find the one you have data in.

                                    T Offline
                                    T Offline
                                    Tejaswini_14
                                    wrote on last edited by
                                    #23

                                    @mrjj It helped me. Thanks a lot!! But I have provided the path as- "C:\Python36\fantcktdb.db"
                                    and also I needed to open and close the database connection for every QRadioButton

                                    JonBJ 1 Reply Last reply
                                    0
                                    • JonBJ JonB

                                      @Tejaswini_14
                                      So since you are using Python sqlite3 library calls, not Qt ones, to access your database this is a Python issue not a Qt one, and you would be better asking that in a Python/SQLite forum. It also means that adding to a QListWidget is not itself an issue.

                                      EDIT This post has crossed with @mrjj's which is quite possibly the cause. If you're not sure where the database file is being picked up, perhaps (temporarily) change your db=sqlite3.connect("fantcktdb.db") to specify the full path to the intended file location.

                                      T Offline
                                      T Offline
                                      Tejaswini_14
                                      wrote on last edited by
                                      #24

                                      @JonB Thanks a lot!! It worked for me.

                                      1 Reply Last reply
                                      0
                                      • T Tejaswini_14

                                        @mrjj It helped me. Thanks a lot!! But I have provided the path as- "C:\Python36\fantcktdb.db"
                                        and also I needed to open and close the database connection for every QRadioButton

                                        JonBJ Offline
                                        JonBJ Offline
                                        JonB
                                        wrote on last edited by
                                        #25

                                        @Tejaswini_14 said in How do I display the records fetched from my database to my listwidget?:

                                        But I have provided the path as- "C:\Python36\fantcktdb.db"

                                        Be careful how you do this in Python. If you have a literal you must double the backslahes, e.g.

                                        db=sqlite3.connect("C:\\Python36\\fantcktdb.db")
                                        

                                        and also I needed to open and close the database connection for every QRadioButton

                                        You should not be doing this. Opening/closing a db is "slow", you should keep a connection open and re-use it.

                                        1 Reply Last reply
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