PyQT6, SQL-Light - show table data in QTableView - what am I missing?

PythonQTMarlem

Hello,
Python 3.9.1
windows 11,
PyQt6

I created a database and a table using SQLiteStudio.

The following Python code successfully connects to the database:

import sys
from PyQt6 import QtGui, QtWidgets
from PyQt6.QtGui import QGuiApplication, QIcon
from PyQt6.QtWidgets import QWidget, QApplication, QLabel, QComboBox, QLineEdit, QPushButton, QFormLayout, QTableWidget, QTableView
from PyQt6.QtCore import *
from PyQt6.QtSql import QSql, QSqlDatabase, QSqlRelation, QSqlRelationalTableModel
import csv


class FensterKlasse(QWidget):
    def __init__(self):
        super().__init__()
        self.table_model = QSqlRelationalTableModel(self)
        self.table_model.setTable("telefon_verwaltung")
        self.table_model.setRelation(1, QSqlRelation('vorname', 'nachname', 'telefonnummer'))
        self.GUI()


    def GUI(self):
        self.setWindowTitle("PyQt6 Telefonnummer-Verwaltung mit Datenbank")

        qtRectangle = self.frameGeometry()
        centerPoint = QtGui.QGuiApplication.primaryScreen().availableGeometry().center()
        qtRectangle.moveCenter(centerPoint)
        self.move(qtRectangle.topLeft())

        self.tabellengrid = QTableView()
        self.tabellengrid.setModel(self.table_model)

        formLayout = QFormLayout()
        formLayout.addRow(self.tabellengrid)
        self.setLayout(formLayout)


def programm_beeden(self):
    QApplication.instance().quit()


db = QSqlDatabase.addDatabase("QSQLITE")
db.setDatabaseName("telefonnummern_verwaltung.db")

app = QApplication([])

app.setStyleSheet("""
    QPushButton:focus { background-color: yellow }
    QLineEdit:focus { background-color: yellow }
    QComboBox:focus { background-color: yellow }
    """)

fenster = FensterKlasse()

if __name__ == '__main__':
    fenster.show()
    sys.exit(app.exec())

My problem: The table is displayed but the data in the table is not. What is still missing?

JonB

@PythonQTMarlem
Start by getting it working with a QSqlTableModel for either of the two tables (test for both). Then change to the QSqlRelationalTableModel, if you have anything wrong there it could lead to no rows.

On a separate matter: I would create the QApplication before the QSqlDatabase, and you are not supposed to have a permanent/global db = QSqlDatabase.addDatabase(...) left around, see https://doc.qt.io/qtforpython/PySide6/QtSql/QSqlDatabase.html#detailed-description

Warning

It is highly recommended that you do not keep a copy of the QSqlDatabase around as a member of a class, as this will prevent the instance from being correctly cleaned up on shutdown. If you need to access an existing QSqlDatabase , it should be accessed with database() . If you chose to have a QSqlDatabase member variable, this needs to be deleted before the QCoreApplication instance is deleted, otherwise it may lead to undefined behavior.

PythonQTMarlem

Thank You. I start to learn with a Youtube-Video.
Do you know a good guide to learn Python Qt and SQL Light?

PythonQTMarlem

It works:

self.table_model = QSqlTableModel()
        self.table_model.setTable("telefon_verwaltung")
        self.table_model.select()
        self.GUI()

The select method was missing.

JonB

@PythonQTMarlem
Yes, I must admit I thought I recalled setTable() did a select(), but per https://doc.qt.io/qt-6/qsqltablemodel.html#setTable

Does not select data from the table, but fetches its field information.

To populate the model with the table's data, call select().

PythonQTMarlem

okay!
Thank you for your post!