def log_in(self):
        user = self.user_entry.get()
        password = self.password_entry.get()
        get_users = ("SELECT * from user WHERE username = %s")
        self.controller.cursor.execute(get_users, (user,))
        uname = self.controller.cursor.fetchone()
        if uname == None:
            tkmb.showerror("Error", "Username not in database.")
        else:
            uname = list(uname)
            if uname[1] != password:
                tkmb.showerror("Error", "Password is incorrect.")
            else:
                self.controller.cnx = mysql.connector.connect(user=user, password=password,
                    host='localhost', database='gt_train')
                self.controller.cursor = self.controller.cnx.cursor()
                self.controller.current_user = user
                print self.controller.current_user
                self.controller.show_frame("ChooseFunctionality_Customer")

        # userExists = False;
        # login_success = False;
        # for (uname, pword) in self.controller.cursor:
        #     if uname==user:
        #         userExists = True;
        #         if pword==password:
        #             login_success = True;
        #         else:
        #             tkmb.showerror("Error", "Password is incorrect.")
        # if not userExists:
        #         tkmb.showerror("Error", "Username not in database.")
        # if login_success:
        #     self.controller.cnx = mysql.connector.connect(user=user, password=password,
        #         host='localhost', database='gt_train')
        #     self.controller.cursor = self.controller.cnx.cursor()
        #     self.controller.current_user = user
        #     self.controller.show_frame("ChooseFunctionality_Customer")