it is showing error

[Pappu Kumar Keshari]

dbmanager.h==>

#ifndef DBMANAGER_H
#define DBMANAGER_H
#include <QObject>
#include <QSqlDatabase>

/**

• \class DbManager

• \brief SQL Database Manager class

• DbManager sets up the connection with SQL database

• and performs some basics queries. The class requires

• existing SQL database. You can create it with sqlite:

• 1. $ sqlite3 people.db
• 2. sqilte> CREATE TABLE people(ids integer primary key, name text);
• 3. sqlite> .quit
     */
     class DbManager : public QObject
     {
     Q_OBJECT
     public:
     explicit DbManager(QObject *parent = nullptr);

  /**

  • @brief Constructor
  • Constructor sets up connection with db and opens it
  • @param path - absolute path to db file
    */
    DbManager(const QString& path);

  /**

  • @brief Destructor
  • Close the db connection
    */
    ~DbManager();

  bool isOpen() const;

  /**

  • @brief Creates a new 'people' table if it doesn't already exist
  • @return true - 'people' table created successfully, false - table not created
    */
    bool createTable();

  /**

  • @brief Add person data to db
  • @param name - name of person to add
  • @return true - person added successfully, false - person not added
    */

  bool addRecord(const QString &name, const QString &fatherName,
  const QString &motherName, const QString &mobileNumber,
  const QString &selectedGender, const QString &qualification,
  const QString &skills, const QString &state,
  const QString &city, const QString &landmark,
  const QString &pincode);

  /**

  • @brief Remove person data from db
  • @param name - name of person to remove.
  • @return true - person removed successfully, false - person not removed
    */
    bool removeRecord(const QString& name);

  /**

  • @brief Check if person of name "name" exists in db
  • @param name - name of person to check.
  • @return true - person exists, false - person does not exist
    */
    bool recordExists(const QString& name) const;

  /**

  • @brief Print names of all persons in db
    */
    void printAllRecords() const;

  /**

  • @brief Remove all persons from db
  • @return true - all persons removed successfully, false - not removed
    */
    bool removeAllRecords();

public slots:

//It will Save Data From QML UI to Sqlite
Q_INVOKABLE bool saveToSqlite(const QString &data);

private:
QSqlDatabase m_db;
};

#endif // DBMANAGER_H

---

filehandler.h==>

#ifndef FILEHANDLER_H
#define FILEHANDLER_H

#include <QObject>

class FileHandler : public QObject
{
Q_OBJECT
public:
explicit FileHandler(QObject *parent = nullptr);

/*Constructor sets up connection with db and opens it
 path - absolute path to db file*/

public slots:
//It will Save Data From QML UI to File
Q_INVOKABLE bool saveToFile(const QString &data);

};

#endif // FILEHANDLER_H

---

dbmanager.cpp==>

#include "dbmanager.h"
#include <QFile>
#include <QTextStream>
#include <QDateTime>
#include <QDebug>

#include <QSqlQuery>
#include <QSqlError>
#include <QSqlRecord>

DbManager::DbManager(QObject *parent) : QObject(parent)
{

}

DbManager::DbManager(const QString &path)
{
m_db = QSqlDatabase::addDatabase("QSQLITE");
m_db.setDatabaseName(path);

if (!m_db.open())
{
    qDebug() << "Error: connection with database fail";
}
else
{
    qDebug() << "Database Connected Successfully !!!";
}
createTable();

}

DbManager::~DbManager()
{
if (m_db.isOpen())
{
m_db.close();
}
}

bool DbManager::isOpen() const
{
return m_db.isOpen();
}

bool DbManager::createTable()
{
bool success = false;

QSqlQuery query;

query.prepare("CREATE TABLE  student (id INTEGER PRIMARY KEY, name TEXT, "
              "  fatherName TEXT, motherName TEXT, mobileNumber TEXT, "
              "gender TEXT, qualification TEXT, skills TEXT, state TEXT, "
              "city TEXT, landmark TEXT, pincode TEXT)");
if (!query.exec())
{
    qDebug() << "Couldn't create the table 'student': one might already exist.";
    success = false;
}

return success;

}

bool DbManager::addRecord(const QString &name, const QString &fatherName,
const QString &motherName, const QString &mobileNumber,
const QString &selectedGender, const QString &qualification,
const QString &skills, const QString &state,
const QString &city, const QString &landmark,
const QString &pincode)
{
if (isOpen())
{
QSqlQuery queryAdd;
queryAdd.prepare("INSERT INTO student (name, fatherName, motherName, mobileNumber, gender, qualification, skills, state, city, landmark, pincode) "
"VALUES (:name, :fatherName, :motherName, :mobileNumber, :gender, :qualification, :skills, :state, :city, :landmark, :pincode)");
queryAdd.bindValue(":name", name);
queryAdd.bindValue(":fatherName", fatherName);
queryAdd.bindValue(":motherName", motherName);
queryAdd.bindValue(":mobileNumber", mobileNumber);
queryAdd.bindValue(":gender", selectedGender);
queryAdd.bindValue(":qualification", qualification);
queryAdd.bindValue(":skills", skills);
queryAdd.bindValue(":state", state);
queryAdd.bindValue(":city", city);
queryAdd.bindValue(":landmark", landmark);
queryAdd.bindValue(":pincode", pincode);

    if (queryAdd.exec())
    {
        return true;
    }
    else
    {
        qDebug() << "Data insertion failed: " << queryAdd.lastError();
    }
}
else
{
    qDebug() << "Database is not open!";
}

return false;

}

bool DbManager::removeRecord(const QString& name)
{
bool success = false;

if (recordExists(name))
{
    QSqlQuery queryDelete;
    queryDelete.prepare("DELETE FROM people WHERE name = (:name)");     ///////////////////////////////////////
    queryDelete.bindValue(":name", name);
    success = queryDelete.exec();

    if(!success)
    {
        qDebug() << "remove person failed: " << queryDelete.lastError();
    }
}
else
{
    qDebug() << "remove person failed: person doesnt exist";
}

return success;

}

void DbManager::printAllRecords() const
{
qDebug() << "Persons in Database:";
QSqlQuery query("SELECT * FROM student");

if (!query.exec())
{
    qDebug() << "Error executing query: " << query.lastError().text();
    return;
}

while (query.next())
{
    QString name = query.value("name").toString();
    QString fatherName = query.value("fatherName").toString();
    QString motherName = query.value("motherName").toString();
    QString mobileNumber = query.value("mobileNumber").toString();
    QString selectedGender = query.value("gender").toString();
    QString qualification = query.value("qualification").toString();
    QString skills = query.value("skills").toString();
    QString state = query.value("state").toString();
    QString city = query.value("city").toString();
    QString landmark = query.value("landmark").toString();
    QString pincode = query.value("pincode").toString();

    qDebug() << "Name: " << name;
    qDebug() << "Father's Name: " << fatherName;
    qDebug() << "Mother's Name: " << motherName;
    qDebug() << "Mobile Number: " << mobileNumber;
    qDebug() << "Gender: " << selectedGender;
    qDebug() << "Qualification: " << qualification;
    qDebug() << "Skills: " << skills;
    qDebug() << "State: " << state;
    qDebug() << "City: " << city;
    qDebug() << "Landmark: " << landmark;
    qDebug() << "Pincode: " << pincode;
}

}

bool DbManager::recordExists(const QString& name) const
{
bool exists = false;

QSqlQuery checkQuery;
checkQuery.prepare("SELECT name FROM people WHERE name = (:name)");              ///////////////////////////////////////
checkQuery.bindValue(":name", name);

if (checkQuery.exec())
{
    if (checkQuery.next())
    {
        exists = true;
    }
}
else
{
    qDebug() << "person exists failed: " << checkQuery.lastError();
}

return exists;

}

bool DbManager::removeAllRecords()
{
bool success = false;

QSqlQuery removeQuery;
removeQuery.prepare("DELETE FROM people");

if (removeQuery.exec())
{
    success = true;
}
else
{
    qDebug() << "remove all persons failed: " << removeQuery.lastError();
}

return success;

}

bool DbManager::saveToSqlite(const QString &data)
{
QStringList list =data.split(",");
qDebug()<<"Input Data" <<list;
//printAllRecords();

addRecord(list.at(0),list.at(1),list.at(2),list.at(3),list.at(4),list.at(5),list.at(6),list.at(7)
          ,list.at(8),list.at(9),list.at(10));

printAllRecords();

}

---

filehandler.cpp==>

#include "filehandler.h"
#include <QFile>
#include <QTextStream>
#include <QDateTime>
#include <QDebug>

FileHandler::FileHandler(QObject *parent) : QObject(parent){

}
bool FileHandler::saveToFile(const QString &data)
{
QString fileName = QDateTime::currentDateTime().toString("dd-mm-yyyy-hh:mm:ss");
fileName +=".txt";

QFile file("/root/Desktop/"+fileName);
if(!file.open(QIODevice::WriteOnly | QIODevice::Text))

    return false;

QTextStream stream(&file);
stream << data;
file.close();

return true;

}

---

main.cpp==>

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include <filehandler.h>
#include <dbmanager.h>
static const QString path = "example.db";

int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
FileHandler fileHandler;

DbManager dbManager(path); //

engine.rootContext()->setContextProperty("file_Handler", &fileHandler);

engine.rootContext()->setContextProperty("d_bmmanager", &dbManager); //

engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

if (engine.rootObjects().isEmpty())
    return -1;

return app.exec();

}

---

main.qml==>

import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Controls 2.12
import QtQuick.Layouts 1.3
import QtQuick.Dialogs 1.2

Window {
id: window
width: 500
height: 700
visible: true
title: qsTr("Student Login Form")
flags: Qt.SplashScreen | Qt.FramelessWindowHint

property string name: ""
property string fatherName: ""
property string motherName: ""
property string mobileNumber: ""
property string rajya: ""
property string city: ""
property string landMark: ""
property string pinCode: ""
property var selectedItems: []
property string selectedGender: ""

//Top Heading
Rectangle{
    id:containerRect
    y: 0
    height: 44
    anchors.left:  parent.left
    anchors.right: parent.right
    anchors.leftMargin: 0
    anchors.rightMargin: 0
    color: "dodgerblue"
    border.color: "#000000"
    border.width: 6

    //Heading Name
    Text{
        width: 245
        height: 29
        anchors.centerIn: parent
        text: "Student Login Form"
        font.family: "Times New Roman"
        anchors.verticalCenterOffset: -5
        anchors.horizontalCenterOffset: 3
        color: "#fefff6"
        font.pointSize: 20
    }

    Button {
        id: button1
        x: 389
        y: 8
        width: 98
        height: 26
        text: qsTr("Close")
        font.bold: true
        MouseArea{
            anchors.fill: parent
            onClicked: {
                Qt.quit();
            }

            Rectangle{
                anchors.centerIn:parent
                width: 98
                height: 26
                radius: 2
                color: "red"
            }
        }
    }
}

Rectangle{

    id:containerRect1
    color: "#f1ffffff"
    radius: 6
    border.color: "#f797187f"
    border.width: 2
    anchors.fill: parent
    anchors.rightMargin: 8
    anchors.bottomMargin: 23
    anchors.leftMargin: 9
    anchors.topMargin: 53

    GroupBox {
        id: groupBox
        height: 312
        anchors.left: parent.left
        anchors.right: parent.right
        anchors.top: parent.top
        anchors.bottomMargin: -1
        layer.textureSize.width: 4
        anchors.rightMargin: 15
        anchors.leftMargin: 11
        anchors.topMargin: 2
        title: qsTr("Personal Details")

        Label  {
            id: label
            x: 50
            y: 17
            text: qsTr("Name")
        }

        Label {
            id: label1
            x: 50
            y: 47
            text: qsTr("Father's Name")
            rotation: -1.907
        }

        Label {
            id: label2
            x: 50
            y: 81
            text: qsTr("Mother's Name")
        }

        Label {
            id: label3
            x: 50
            y: 123
            text: qsTr("Mobile Number")
        }

        Label {
            id: label4
            x: 50
            y: 164
            width: 49
            height: 30
            text: qsTr("Gender")
        }

        Label {
            id: label5
            x: 50
            y: 211
            text: qsTr("Qualification")
        }

        TextField {
            id: nameTextField
            x: 175
            y: 8
            width: 238
            height: 29
            text: "Pappu"
            placeholderText: qsTr("Enter your name")
            onTextChanged: name=text
        }

        TextField {
            id: fatherNameTextField
            x: 175
            y: 44
            width: 238
            height: 29
            text: "Father Name"
            placeholderText: qsTr("Enter your Father's name ")
            onTextChanged: fatherName=text
        }

        TextField {
            id: motherNameTextField
            x: 175
            y: 81
            width: 238
            height: 29
            text: "Mother name"
            placeholderText: qsTr("Enter your Mother's name ")
            onTextChanged: motherName=text
        }

        TextField {
            id: mobileNumberTextField
            x: 175
            y: 123
            width: 238
            height: 29
            text: "85254"
            placeholderText: qsTr("Enter your mobile number")
            onTextChanged: mobileNumber=text
        }

        RowLayout{
            x: 165
            y: 160
            scale: 0.9
            RadioButton{
                text: "Male"
                checked: selectedGender==="Male"
                onClicked: {
                    if(checked) selectedGender="Male"
                }
            }
            RadioButton{
                text: "Female"
                checked: selectedGender==="Female"
                onClicked: {
                    if(checked) selectedGender="Female"
                }
            }
        }

        ComboBox {
            id: comboBox
            x: 178
            y: 206
            width: 140
            height: 30
            model: ["--Select--","10th","12th","Graduation","Post Graduation"]
        }

        Label {
            id: label10
            x: 50
            y: 244
            text: qsTr("Skills")
        }


        Row{
            spacing: 10
            x: 170
            y: 235

            CheckBox {
                id: checkBoxC
                text: qsTr("C")
                checked: true
            }

            CheckBox {
                id: checkBoxCPlusPlus
                text: qsTr("C++")
            }

            CheckBox {
                id: checkBoxQt
                text: qsTr("Qt")
            }
        }

    }

    GroupBox {
        id: groupBox1
        height: 254
        anchors.left: parent.left
        anchors.right: parent.right
        anchors.top: parent.top
        anchors.rightMargin: 13
        anchors.leftMargin: 13
        anchors.topMargin: 314
        title: qsTr("Address")

        Label {
            id: label6
            x: 50
            y: 27
            width: 53
            height: 20
            text: qsTr("State")
        }

        Label {
            id: label7
            x: 50
            y: 72
            width: 50
            height: 20
            text: qsTr("City")
        }

        Label {
            id: label8
            x: 50
            y: 125
            width: 83
            height: 20
            text: qsTr("Land mark")
        }

        Label {
            id: label9
            x: 50
            y: 175
            width: 61
            height: 20
            text: qsTr("Pincode")
        }

        TextField {
            id: stateTextField
            x: 178
            y: 21
            width: 238
            height: 29
            text: "Kar"
            placeholderText: qsTr("Enter your State")
            onTextChanged: rajya=text
        }

        TextField {
            id: cityTextField
            x: 178
            y: 72
            width: 238
            height: 29
            text: "Bang"
            placeholderText: qsTr("Enter your City ")
            onTextChanged:city=text
        }

        TextField {
            id: landmarkTextField
            x: 175
            y: 126
            width: 238
            height: 29
            text: "BEL"
            placeholderText: qsTr("Enter your Landmark ")
            onTextChanged: landMark=text
        }

        TextField {
            id: pincodeTextField
            x: 175
            y: 176
            width: 238
            height: 29
            text: "560013"
            placeholderText: qsTr("Enter your Pincode ")
            onTextChanged: pinCode=text
        }
    }

    Button {
        id: button
        x: 172
        y: 568
        width: 99
        height: 37
        text: qsTr("Submit")
        layer.format: ShaderEffectSource.RGB
        font.weight: Font.Bold
        font.underline: false
        font.strikeout: false
        font.bold: true
        font.family: "Verdana"



        onClicked: {

            //It will show Data From UI to Console
            //                console.log("Name is :",name)
            //                console.log("Father's Name is :",fatherName)
            //                console.log("Mother's Name is :",motherName)
            //                console.log("Mobile Number is :",mobileNumber)
            //                console.log("Gender is :",selectedGender)

            var selectedItem=comboBox.currentText
            var selectedIndex=comboBox.currentIndex
            if(selectedIndex==0)
            {
                //                    console.log("Qualification is :",)
            }
            else
            {
                //                    console.log("Qualification is :",selectedItem)
            }

            selectedItems=[];
            if(checkBoxC.checked)
                selectedItems.push(checkBoxC.text)
            if(checkBoxCPlusPlus.checked)
                selectedItems.push(checkBoxCPlusPlus.text)
            if(checkBoxQt.checked)
                selectedItems.push(checkBoxQt.text)
            //                console.log("Skills :",selectedItems.toString())
            //                console.log("State is :",rajya)
            //                console.log("City is :",city)
            //                console.log("Land Mark is :",landMark)
            //                console.log("Pincode is :",pinCode)


            //Save Data From UI to Text File
            var dataToSave =
                    "Student's Name is : "+ nameTextField.text + "\n" +
                    "Father's Name is : "+ fatherNameTextField.text +"\n"+
                    "Mother's Name is : "+ motherNameTextField.text +"\n"+
                    "Mobile Number is : "+ mobileNumberTextField.text +"\n"+
                    "Gender is : "+ selectedGender +"\n"+
                    "Qualification is : "+ selectedItem.toString() +"\n"+
                    "Skills : "+ selectedItems +"\n"+
                    "State is : "+ stateTextField.text +"\n"+
                    "City is : "+ cityTextField.text +"\n"+
                    "Landmark is : "+ landmarkTextField.text +"\n"+
                    "Pincode is : "+ pincodeTextField.text ;

            if (file_Handler.saveToFile(dataToSave))
            {
                console.log("Data saved to file successfully.");
            }
            else
            {
                console.error("Error saving data to file.");
            }



            //Save Data From UI to Sqlite
            var skillsTxt = selectedItems.join(":").toString();
            var csv_data =
                    nameTextField.text + "," +
                    fatherNameTextField.text +","+
                    motherNameTextField.text +","+
                    mobileNumberTextField.text +","+
                    selectedGender +","+
                    selectedItem+","+
                    skillsTxt +","+
                    stateTextField.text +","+
                    cityTextField.text +","+
                    landmarkTextField.text +","+
                    pincodeTextField.text ;

            if (d_bmmanager.saveToSqlite(csv_data))
            {
                console.log("Data saved to Sqlite successfully.");
            }
            else
            {
                console.error("Error saving data to Sqlite.");
            }


            //It will Reset all field as blank
            nameTextField.text=""
            fatherNameTextField.text=""
            motherNameTextField.text=""
            mobileNumberTextField.text=""
            mobileNumberTextField.text=""
            stateTextField.text=""
            cityTextField.text=""
            landmarkTextField.text=""
            pincodeTextField.text=""

            //When Click on Save Button It will Display message "Data Saved Successfully !!!" and Main window will close
            var messageDialog = Qt.createQmlObject('import QtQuick.Dialogs 1.2; MessageDialog{}',parent);
            messageDialog.text = "Data Saved Successfully !!!";
            messageDialog.standardButtons = StandardButton.Ok;
            messageDialog.accepted.connect(function(){
                //Close the window when "OK" button is clicked
                window.close();
            });
            messageDialog.open();
        }

        Rectangle{
            anchors.centerIn: parent
            width: 99
            height: 37
            color: "green"
            anchors.verticalCenterOffset: 2
            anchors.horizontalCenterOffset: 0
        }
    }
}

}

[Christian Ehrlicher]

I doubt someone will go through all this stuff and find out what's wrong. Esp. Since you did not say what error and where it occurs. Please provide a minimal, compilable example of your problem.

[Axel Spoerl]

Adding to @Christian-Ehrlicher: Please show the exact error output, and please format the code correctly.

[SGaist]

Hi,

To add to my fellows, it looks like a duplicate of this thread.

[ChrisW67]

@Pappu-Kumar-Keshari First, you need to heed the warning your compiler is probably giving you:

dbmanager.cpp: In member function ‘bool DbManager::saveToSqlite(const QString&)’:
dbmanager.cpp:219:1: warning: no return statement in function returning non-void [-Wreturn-type]
  219 | }
      | ^

The code compiles and runs with no error message like:

Getting error when saving file from QML to Sqlite. Error like this =>Property 'saveToSqlite' of object QObject(0x7ffcfa692910) is not a function

The GUI disappears when I click on any of the buttons, does not exit, but also does not save anything into the people table. This is the limit of the effort I can put into debugging your code.

Linux, Qt 6.4.2, GCC 11.4