Connecting methods to custom QListView widgets - PyQt5 & postgreSQL - postgresql

Question

I have a simple Qt application which adds and lists records retrieved from a postgresql db in a QListView using custom widgets. I am having some difficulty setting up a pushbutton (bottom left corner of each list item instance) which will effectively use the record primary key (of the instance) to delete the record from the db
from PyQt5 import QtCore, QtWidgets
import psycopg2
import sys
import dbAPP_GUI
import listItem_GUI
class dbAPP(QtWidgets.QMainWindow, dbAPP_GUI.Ui_MainWindow):
def __init__(self, parent=None):
super(dbAPP, self).__init__(parent)
self.setupUi(self)
self.conn = psycopg2.connect(database="Name", user="anthony#primeinstr.co.za"
, password="14581458", host="127.0.0.1")
self.ListItemLine = listItem()
# ==============
# CONNECTIONS
# ==============
self.btn_save.clicked.connect(self.writeData)
self.tabWidget.currentChanged.connect(self.fetchData)
self.btn_go.clicked.connect(self.searchData)
# =============
# METHODS
# =============
def writeData(self):
name = self.name_lineEdit.text()
surn = self.surname_lineEdit.text()
age = self.age_lineEdit.text()
address = self.address_lineEdit.text()
if len(name) > 0:
c = self.conn.cursor()
c.execute(" INSERT INTO info (name, surname, age, address)"
"VALUES (%s, %s, %s, %s)", (name, surn, age, address))
self.conn.commit()
QtWidgets.QMessageBox.information(self, "Notice", "Information was successfully written to database")
self.name_lineEdit.clear()
self.surname_lineEdit.clear()
self.age_lineEdit.clear()
self.address_lineEdit.clear()
else:
QtWidgets.QMessageBox.warning(self, "Warning", "The name field is empty, please enter a value")
def fetchData(self):
self.listWidget.clear()
lineNo = 0
c = self.conn.cursor()
c.execute("SELECT * FROM info;")
listing = c.fetchall()
for i in listing:
name = (str(i[:1]).replace("(", "").replace(")", "").replace("'", "").replace(",", ""))
surn = (str(i[1:2]).replace("(", "").replace(")", "").replace("'", "").replace(",", ""))
age = (str(i[2:3]).replace("(", "").replace(")", "").replace("'", "").replace(",", ""))
address = (str(i[3:4]).replace("(", "").replace(")", "").replace("'", "").replace(",", ""))
ID = (str(i[4:5]).replace("(", "").replace(")", "").replace("'", "").replace(",", ""))
nameSurn = name + " " + surn
lineNo += 1
label = listItem()
label.num_label.setText(str(lineNo))
label.nameSurn_label.setText(nameSurn)
label.age_label.setText(age)
label.address_label.setText(address)
label.id_label.setText(ID)
x = QtWidgets.QListWidgetItem()
x.setSizeHint(QtCore.QSize(280, 60))
self.listWidget.addItem(x)
self.listWidget.setItemWidget(x, label)
label.show()
def searchData(self):
self.listWidget_2.clear()
lineNo = 0
c = self.conn.cursor()
c.execute("SELECT * FROM info;")
results = c.fetchall()
for i in results:
name = (str(i[:1]).replace("(", "").replace(")", "").replace("'", "").replace(",", ""))
surn = (str(i[1:2]).replace("(", "").replace(")", "").replace("'", "").replace(",", ""))
age = (str(i[2:3]).replace("(", "").replace(")", "").replace("'", "").replace(",", ""))
address = (str(i[3:4]).replace("(", "").replace(")", "").replace("'", "").replace(",", ""))
nameSurn = name + " " + surn
if str(self.search_lineEdit.text()).lower() == name.lower()\
or str(self.search_lineEdit.text()).lower() == surn.lower()\
or str(self.search_lineEdit.text()).lower() == address.lower():
lineNo += 1
label = listItem()
label.num_label.setText(str(lineNo))
label.nameSurn_label.setText(nameSurn)
label.age_label.setText(age)
label.address_label.setText(address)
x = QtWidgets.QListWidgetItem()
x.setSizeHint(QtCore.QSize(280, 60))
self.listWidget_2.addItem(x)
self.listWidget_2.setItemWidget(x, label)
label.show()
# ======================================================================================================================
class listItem(QtWidgets.QWidget, listItem_GUI.Ui_lineItem):
def __init__(self, parent=None):
super(listItem, self).__init__(parent)
self.setWindowFlags(QtCore.Qt.FramelessWindowHint)
self.setupUi(self)
self.btn_del.clicked.connect(self.delData)
def delData(self):
ID = self.id_label.text()
print(ID)
c = psycopg2._ext.connection.cursor()
c.execute("DELETE FROM info WHERE id=(%s)", (ID))
# ======================================================================================================================
app = QtWidgets.QApplication(sys.argv)
app.setStyle("fusion")
main = dbAPP()
main.show()
List = listItem()
List.hide()
sys.exit(app.exec_())
Currently it's failing because the cursor object in the method "DelData" requires an argument. If however this is the correct way of doing this, I can honestly not say. So if anyone has any better suggestions, that could also work. I'm just trying to find my feet with PyQt, postgreSQL and Python :)

Answer 1

The second argument to execute is a sequence or mapping. But you are effectively passing a string, because a tuple is primarily defined by commas, not parentheses.
So you should either do this:
c.execute("DELETE FROM info WHERE id=%s", (ID,)) # tuple
or this:
c.execute("DELETE FROM info WHERE id=%s", [ID]) # list
or this:
c.execute("DELETE FROM info WHERE id=%(ID)s", {'ID': ID}) # dict