More description to help understand the case.

I want to populate a tableview with user data stored inside a SQLite DB. In the main.c I connect to DB and register the CredentialsModel as a Type:

Qt Code: 
  1. #include <QGuiApplication>
  2. #include <QQmlApplicationEngine>
  3. #include <QQmlContext>
  4. #include <QStandardPaths>
  5. #include <QSqlDatabase>
  6. #include <QSqlError>
  7. #include <QtQml>
  8.  
  9. #include "sqlcredentialsmodel.h"
  10.  
  11. static void connectToDatabase()
  12. {
  13.     QSqlDatabase database = QSqlDatabase::database();
  14.     if (!database.isValid()) {
  15.         database = QSqlDatabase::addDatabase("QSQLITE");
  16.         if (!database.isValid())
  17.             qFatal("Cannot add database: %s", qPrintable(database.lastError().text()));
  18.     }
  19.  
  20.     const QDir writeDir = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
  21.     if (!writeDir.mkpath("."))
  22.         qFatal("Failed to create writable directory at %s", qPrintable(writeDir.absolutePath()));
  23.  
  24.     // Ensure that we have a writable location on all devices.
  25.     const QString fileName = writeDir.absolutePath() + "/chat-database.sqlite3";
  26.     qDebug()<< "file: "<<fileName;
  27.     // When using the SQLite driver, open() will create the SQLite database if it doesn't exist.
  28.     database.setDatabaseName(fileName);
  29.     if (!database.open()) {
  30.         qFatal("Cannot open database: %s", qPrintable(database.lastError().text()));
  31.         QFile::remove(fileName);
  32.     }
  33. }
  34.  
  35. int main(int argc, char *argv[])
  36. {
  37.     QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
  38.  
  39.     QGuiApplication app(argc, argv);
  40.  
  41.     connectToDatabase();
  42.  
  43.     QQmlApplicationEngine engine;
  44.     qmlRegisterType<SqlCredentialsModel>("credentials", 1, 0, "SqlCredentialsModel");
  45.  
  46.     const QUrl url(QStringLiteral("qrc:/main.qml"));
  47.     QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
  48.                      &app, [url](QObject *obj, const QUrl &objUrl) {
  49.         if (!obj && url == objUrl)
  50.             QCoreApplication::exit(-1);
  51.     }, Qt::QueuedConnection);
  52.     engine.load(url);
  53.  
  54.     return app.exec();
  55. }
To copy to clipboard, switch view to plain text mode 

The model is implemented as following:

sqlcredentialsmodel.h

Qt Code: 
  1. #ifndef SQLCREDENTIALSMODEL_H
  2. #define SQLCREDENTIALSMODEL_H
  3.  
  4. #include <QSqlQueryModel>
  5.  
  6. class SqlCredentialsModel : public QSqlQueryModel
  7. {
  8. public:
  9.     SqlCredentialsModel(QObject *parent = 0);
  10. };
  11.  
  12. #endif // SQLCREDENTIALSMODEL_H
To copy to clipboard, switch view to plain text mode 


sqlcredentialsmodel.cpp

Qt Code: 
  1. #include "sqlcredentialsmodel.h"
  2.  
  3. #include <QDebug>
  4. #include <QSqlError>
  5. #include <QSqlQuery>
  6.  
  7. static void createTable()
  8. {
  9.     for (auto table: QSqlDatabase::database().tables()){
  10.         qDebug()<<"table "<<table;
  11.     }
  12.  
  13.     if (QSqlDatabase::database().tables().contains(QStringLiteral("Credentials"))) {
  14.         // The table already exists; we don't need to do anything.
  15.         return;
  16.     }
  17.  
  18.     QSqlQuery query;
  19.     if (!query.exec(
  20.         "CREATE TABLE IF NOT EXISTS 'Credentials' ("
  21.         "   'username', 'password' TEXT NOT NULL,"
  22.         "   PRIMARY KEY(username)"
  23.         ")")) {
  24.         qFatal("Failed to query database: %s", qPrintable(query.lastError().text()));
  25.     }
  26.  
  27.     query.exec("INSERT INTO Credentials VALUES('bert', 'b&c' )");
  28.     query.exec("INSERT INTO Credentials VALUES('emmy', 'e&c' )");
  29.     query.exec("INSERT INTO Credentials VALUES('hans', 'h&c' )");
  30. }
  31.  
  32. SqlCredentialsModel::SqlCredentialsModel(QObject *parent) :
  34. {
  35.     createTable();
  36.  
  37.     QSqlQuery query;
  38.  
  39.     if (!query.exec("SELECT * FROM Credentials"))
  40.         qFatal("Contacts SELECT query failed: %s", qPrintable(query.lastError().text()));
  41.  
  42.     setQuery(query);
  43.     if (lastError().isValid())
  44.         qFatal("Cannot set query on SqlCredentialsModel: %s", qPrintable(lastError().text()));
  45. }
To copy to clipboard, switch view to plain text mode 

QML is implemented as following:

main.qml

Qt Code: 
  1. import QtQuick 2.12
  2. import QtQuick.Controls 2.5
  3.  
  4. ApplicationWindow {
  5.     visible: true
  6.     width: 100
  7.     height: 120
  8.     title: qsTr("Credentials")
  9.  
  10.     SwipeView {
  11.         id: swipeView
  12.         anchors.fill: parent
  13.  
  14.         CredentialsView{
  15.             id: credentialsView
  16.         }
  17.     }
  18. }
To copy to clipboard, switch view to plain text mode 


CredentialsView.ui.qml

Qt Code: 
  1. import QtQuick 2.9
  2. import QtQuick.Controls 2.2
  3. import QtQuick.Layouts 1.3
  4.  
  5. import credentials 1.0
  6.  
  7. Page {
  8.     id: page_Credentials
  9.     header: Label {
  10.         text: qsTr("Credentials")
  11.         font.pixelSize: Qt.application.font.pixelSize
  12.         padding: 10
  13.     }
  14.  
  15.     CredentialsTableView{
  16.         anchors.fill: parent
  17.     }
  18.  
  19. }
To copy to clipboard, switch view to plain text mode 

CredentialsTableView.ui.qml

Qt Code: 
  1. import QtQuick 2.12
  2. import QtQuick.Controls 2.12
  3.  
  4. import credentials 1.0
  5.  
  6. TableView {
  7.     id: credentialsTableView
  8.     property alias credentialsTableView: credentialsTableView
  9.     anchors.fill: parent
  10.     columnSpacing: 2
  11.     rowSpacing: 2
  12.     clip: true
  13.  
  14.     model: SqlCredentialsModel{}
  15.     delegate: Rectangle {
  16.         color: "lightblue"
  17.         implicitWidth: lbl_tableCell.width
  18.         implicitHeight: lbl_tableCell.height
  19.         Label {
  20.             id: lbl_tableCell
  21.             text: display
  22.         }
  23.     }
  24. }
To copy to clipboard, switch view to plain text mode 

Thanks in advance