如何使用 PySide2 向我的 SQLite 數據庫添加具有 NULL 值的記錄？

Question

我有一個 PySide2 GUI，可以在我的 SQLite3 數據庫中添加、更新和刪除記錄。 我使用 QTableView 查看數據，使用 QDataWidgetMapper 編輯數據。

我的問題是，當我向數據庫中添加一條在任何字段中都有空白值的記錄時，它不會在數據庫中注冊為 NULL 值，只有一個空白字符串 ("")。 我認為我沒有以正確的方式實施委托。 我應該在列上還是在 QDataWidgetMapper 上設置委托？

import sys
import os
from PySide2 import QtCore, QtGui, QtWidgets, QtSql
import PySide2.QtUiTools as QtUiTools
import sqlite3


class NullDelegate(QtWidgets.QStyledItemDelegate):
    def __init__(self, parent=None):
        super(NullDelegate, self).__init__(parent)

    def createEditor(self, parent, options, index):
        editor = QtWidgets.QLineEdit(parent)
        return editor

    def setEditorData(self, editor, index):
        if index.siblingAtColumn(1).data() == "":  # This is for testing purposes
            print(index.siblingAtColumn(2).data())
        if index.data():
            editor.setText(str(index.data()))
        editor.selectAll()  # This is for testing purposes

    def setModelData(self, editor, model, index):
        value = editor.text()
        if value == "":
            print("null value")
            model.setData(index, None, QtCore.Qt.EditRole)
        else:
            model.setData(index, value, QtCore.Qt.EditRole)


class Main(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(Main, self).__init__(parent)
        # load ui file
        loader = QtUiTools.QUiLoader()
        # The UI file must be a widget, NOT MainWindow, to load into a QMainWindow object
        # otherwise you will have to use .show() to open in separate window
        path = os.path.join(os.path.dirname(__file__), "main.ui")
        self.main = loader.load(path, self)

        # create SQLite Database and Table
        db = QtSql.QSqlDatabase.addDatabase("QSQLITE")
        db.setDatabaseName("customers_demo.db")
        if db.open():
            print('connection open')
        query = QtSql.QSqlQuery(db=db)
        query.prepare("CREATE TABLE IF NOT EXISTS Customers_demo (ID INT PRIMARY KEY, FEIN varchar(255), CustomerName varchar(255), Address varchar(255), City varchar(255), State varchar(255), Zip INT) ")
        query.exec_()

        # Set up QSqlTableModel
        self.model = QtSql.QSqlTableModel(self)
        self.model.setTable("customers_demo")
        self.model.select()

        # Set up QDataWidgetMapper
        self.mapper = QtWidgets.QDataWidgetMapper()
        self.mapper.setModel(self.model)

        # Set up the delegate for null values
        null_delegate = NullDelegate(self.main.tableView)
        self.mapper.setItemDelegate(null_delegate)

        # Configure QDataWidgetMapper
        self.mapper.addMapping(self.main.id_lineEdit, 0)
        self.mapper.addMapping(self.main.fein_lineEdit, 1)
        self.mapper.addMapping(self.main.customer_lineEdit, 2)
        self.mapper.addMapping(self.main.address_lineEdit, 3)
        self.mapper.addMapping(self.main.city_lineEdit, 4)
        self.mapper.addMapping(self.main.state_lineEdit, 5)
        self.mapper.addMapping(self.main.zip_lineEdit, 6)
        self.mapper.setSubmitPolicy(self.mapper.ManualSubmit)

        # Set up QTableView
        self.main.tableView.setModel(self.model)
        # Set up the delegate for null values
        # null_delegate = NullDelegate(self.main.tableView)
        # self.main.tableView.setItemDelegateForColumn(1, null_delegate)
        self.main.tableView.resizeColumnsToContents()

        # QTableView properties
        self.main.tableView.setSortingEnabled(True)  # sort by clicking title
        self.main.tableView.resizeColumnToContents(2)  # "Customer Name" column
        self.main.tableView.setSelectionBehavior(
            QtWidgets.QAbstractItemView.SelectRows)
        # add background color to every other row
        self.main.tableView.setAlternatingRowColors(True)
        # make table uneditable
        self.main.tableView.setEditTriggers(
            QtWidgets.QTableView.NoEditTriggers)

        self.mapper.setCurrentIndex(0)
        print(self.mapper.currentIndex())

        self.RECORD_NUMBER()
        self.handle_buttons()

    def handle_buttons(self):
        self.main.update_btn.clicked.connect(self.UPDATE)
        self.main.delete_btn.clicked.connect(self.DELETE)
        self.main.new_btn.clicked.connect(self.NEW)
        self.main.first_btn.clicked.connect(self.mapper.toFirst)
        self.main.first_btn.clicked.connect(self.RECORD_NUMBER)
        self.main.previous_btn.clicked.connect(self.mapper.toPrevious)
        self.main.previous_btn.clicked.connect(self.RECORD_NUMBER)
        self.main.next_btn.clicked.connect(self.mapper.toNext)
        self.main.next_btn.clicked.connect(self.RECORD_NUMBER)
        self.main.last_btn.clicked.connect(self.mapper.toLast)
        self.main.last_btn.clicked.connect(self.RECORD_NUMBER)
        self.main.tableView.clicked.connect(self.SELECT_ROW)

    def SELECT_ROW(self, item):

        # Set text to the selected customer info
        self.main.id_lineEdit.setText(
            str(item.siblingAtColumn(0).data()))  # convert int to str
        self.main.customer_lineEdit.setText(item.siblingAtColumn(2).data())
        self.main.fein_lineEdit.setText(item.siblingAtColumn(1).data())
        self.main.address_lineEdit.setText(item.siblingAtColumn(3).data())
        self.main.city_lineEdit.setText(item.siblingAtColumn(4).data())
        self.main.state_lineEdit.setText(item.siblingAtColumn(5).data())
        self.main.zip_lineEdit.setText(
            str(item.siblingAtColumn(6).data()))  # convert int to str
        self.mapper.setCurrentIndex(item.row())
        self.RECORD_NUMBER()

    def UPDATE(self):
        loader = QtUiTools.QUiLoader()
        path = os.path.join(os.path.dirname(__file__), "dialog.ui")
        dialog = loader.load(path)

        currentIndex = self.mapper.currentIndex()
        print("Mapper", currentIndex)
        self.main.tableView.selectRow(currentIndex)

        customer = self.main.tableView.currentIndex().siblingAtColumn(2).data()
        print(customer)

        text = f"Are you sure you want to UPDATE {customer} info?"
        dialog.label.setText(text)

        dialog.buttonBox.accepted.connect(dialog.accept)
        dialog.buttonBox.rejected.connect(dialog.reject)

        dialog.show()

        if dialog.exec_():
            print("update")
            te = self.mapper.submit()
            print(te)
            print(self.mapper.model())

            self.model.select()
        else:
            pass

    def DELETE(self):
        loader = QtUiTools.QUiLoader()
        path = os.path.join(os.path.dirname(__file__), "dialog.ui")
        dialog = loader.load(path)

        currentIndex = self.mapper.currentIndex()
        print("Mapper", currentIndex)
        self.main.tableView.selectRow(currentIndex)
        customer = self.main.tableView.currentIndex().siblingAtColumn(2).data()
        print(customer)

        text = f"Are you sure you want to DELETE {customer} info?"
        dialog.label.setText(text)

        dialog.buttonBox.accepted.connect(dialog.accept)
        dialog.buttonBox.rejected.connect(dialog.reject)

        dialog.show()

        if dialog.exec_():
            print("yes")

            self.model.removeRow(currentIndex)

            self.model.select()
        else:
            pass
        self.mapper.setCurrentIndex(0)
        print(self.mapper.currentIndex())
        self.RECORD_NUMBER()

    def NEW(self):
        loader = QtUiTools.QUiLoader()
        path = os.path.join(os.path.dirname(__file__), "dialog.ui")
        dialog = loader.load(path)

        customer = self.main.customer_lineEdit.text()
        text = f"Are you sure you want to ADD {customer} info?"
        dialog.label.setText(text)

        dialog.buttonBox.accepted.connect(dialog.accept)
        dialog.buttonBox.rejected.connect(dialog.reject)

        dialog.show()

        if dialog.exec_():
            row = self.model.rowCount()
            record = self.model.record()
            # record.setGenerated('id', False)
            record.setValue('ID', self.main.id_lineEdit.text())
            record.setValue('FEIN', str(self.main.fein_lineEdit.text()))
            record.setValue("CustomerName",
                            self.main.customer_lineEdit.text())
            record.setValue('Address', self.main.address_lineEdit.text())
            record.setValue('City', self.main.city_lineEdit.text())
            record.setValue('State', self.main.state_lineEdit.text())
            record.setValue('Zip', self.main.zip_lineEdit.text())
            self.model.insertRecord(row, record)

            self.model.select()
        else:
            pass
        self.mapper.setCurrentIndex(0)
        print(self.mapper.currentIndex())
        self.RECORD_NUMBER()

    def RECORD_NUMBER(self):
        currentIndex = self.mapper.currentIndex()
        print(currentIndex)
        rows = self.model.rowCount()
        self.main.record_label.setText(
            f"Customer {currentIndex+1} of {rows} customers")


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    widget = Main()
    widget.show()
    app.exec_()

您可以在此處下載 ui 文件和示例數據庫。

我也在使用 Python 3.7.4

Answer 1

問題不在於委托，而在於添加行的代碼，因為您直接傳遞 QLineEdits 的文本而不實現空值的邏輯。

def NEW(self):
    loader = QtUiTools.QUiLoader()
    path = os.path.join(os.path.dirname(__file__), "dialog.ui")
    dialog = loader.load(path)

    customer = self.main.customer_lineEdit.text()
    text = f"Are you sure you want to ADD {customer} info?"
    dialog.label.setText(text)

    dialog.buttonBox.accepted.connect(dialog.accept)
    dialog.buttonBox.rejected.connect(dialog.reject)

    if dialog.exec_():
        mapping = {
            "ID": self.main.id_lineEdit,
            "FEIN": self.main.fein_lineEdit,
            "CustomerName": self.main.customer_lineEdit,
            "Address": self.main.address_lineEdit,
            "City": self.main.city_lineEdit,
            "State": self.main.state_lineEdit,
            "Zip": self.main.zip_lineEdit,
        }
        record = self.model.record()
        for fieldname, lineedit in mapping.items():
            text = lineedit.text()
            record.setValue(fieldname, text if text else None)
        row = self.model.rowCount()
        self.model.insertRecord(row, record)
        self.model.select()
    self.mapper.setCurrentIndex(0)
    print(self.mapper.currentIndex())
    self.RECORD_NUMBER()