How to pull data from QT to Python variable?

Question

Python

Good evening gentlemen :)
I'm practicing with QT Designer and I wanted to implement queries to the database (SQL) GUI.
QT Designer sketched a window, punched a link to a copy when a button was pressed.
UI code in Python. (Graphic arts)

# -*- coding: utf-8 -*-



from PyQt4 import QtCore, QtGui

try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    def _fromUtf8(s):
        return s

try:
    _encoding = QtGui.QApplication.UnicodeUTF8
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig)

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName(_fromUtf8("MainWindow"))
        MainWindow.resize(800, 600)
        self.centralwidget = QtGui.QWidget(MainWindow)
        self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
        self.backendsql = QtGui.QFrame(self.centralwidget)
        self.backendsql.setGeometry(QtCore.QRect(10, 10, 771, 461))
        self.backendsql.setFrameShape(QtGui.QFrame.StyledPanel)
        self.backendsql.setFrameShadow(QtGui.QFrame.Raised)
        self.backendsql.setObjectName(_fromUtf8("backendsql"))
        self.zapros = QtGui.QLineEdit(self.backendsql)
        self.zapros.setGeometry(QtCore.QRect(10, 10, 741, 431))
        self.zapros.setCursor(QtGui.QCursor(QtCore.Qt.IBeamCursor))
        self.zapros.setLayoutDirection(QtCore.Qt.LeftToRight)
        self.zapros.setAutoFillBackground(False)
        self.zapros.setText(_fromUtf8(""))
        self.zapros.setObjectName(_fromUtf8("zapros"))
        self.sql = QtGui.QPushButton(self.centralwidget)
        self.sql.setGeometry(QtCore.QRect(190, 470, 401, 71))
        self.sql.setObjectName(_fromUtf8("sql"))
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtGui.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
        self.menubar.setObjectName(_fromUtf8("menubar"))
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtGui.QStatusBar(MainWindow)
        self.statusbar.setObjectName(_fromUtf8("statusbar"))
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QObject.connect(self.sql, QtCore.SIGNAL(_fromUtf8("clicked()")), self.zapros.copy)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow", None))
        self.sql.setText(_translate("MainWindow", "Отправить запросище", None))

Output:

My script ( Loading graphics and waiting for a variable )

#!/usr/bin/python
# -*- coding: utf-8 -*-
# python 2.7
# ------------------------------------------------

import sys,sqlite3
from PyQt4 import QtGui, uic,QtCore



class MainWindow(QtGui.QMainWindow):
    def __init__(self):
        QtGui.QMainWindow.__init__(self)
        uic.loadUi('sql.ui', self)
        # sql =

    def sql(sql):
        con = sqlite3.connect("students.db")
        cur = con.cursor()  # Создаем объект-курсор
        try:
            cur.executescript(sql)
        except sqlite3.DatabaseError, err:
            print u"Ошибка:", err
        else:
            print u"Запрос успешно выполнен"
        cur.close()
        con.close()


app = QtGui.QApplication(sys.argv)
w = MainWindow()
w.show()
w.setWindowTitle(u"SQL Rishat")
sys.exit(app.exec_())

My script that should launch the graphical interface, get data from it on a button click. (The query that the user entered in the graphical interface)
Actually the question is this. How to implement it?
help me please

Answer 1

"I made a connection to a copy when the button was pressed" it's not at all clear what they were trying to do.
I recommend making the onSendButtonClicked method in MainWindow, and making a connection to it instead of what you have.
Well, it already has something like text = self.uic.zapros.text()