AttributeError: 'str' object has no attribute 'fetch'

Python Help
1

I’m trying to get working the python code at the following website:

After several days I’m still not able to succeed since it stucks giving the recurring error message AttributeError: ‘str’ object has no attribute 'fetch’

2

The complete “message” you get (called a traceback) contains much more information than what you have included. This extra information is needed to figure out what exactly went wrong with your program.

Try to remove as many lines of your code as you can while still getting this error message. Then, post your code here, and also include the complete traceback.

3

Somewhere in your code, I’m guessing that you have a line like this:

db = 'path/to/my/database.db'

You need to change it to

db = Database(‘path/to/my/database.db’)

But you really should post the full traceback of the error.

4

Thanks a lot for your kind and prompt replies and my apologies for the missed information.

Here is the whole code:

#!/usr/bin/env python3

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

from tkinter import *
from tkinter.ttk import Treeview

#GUI creation. Frame contains labels and buttons. 4 frames: search, input, buttons, results.
app = Tk()
frame_search = Frame(app)
frame_search.grid(row=0, column=0)

lbl_search = Label(frame_search, text='Search by hostname', font=('bold', 12), pady=20)
lbl_search.grid(row=0, column=0, sticky=W)
hostname_search = StringVar()
hostname_search_entry = Entry(frame_search, textvariable=hostname_search)
hostname_search_entry.grid(row=0, column=1)

lbl_search = Label(frame_search, text='Search by Query', font=('bold', 12), pady=20)
lbl_search.grid(row=1, column=0, sticky=W)
query_search = StringVar()
query_search.set("Select * from routers where ram>1024")
query_search_entry = Entry(frame_search, textvariable=query_search, width=40)
query_search_entry.grid(row=1, column=1)

#db fields frame
frame_fields = Frame(app)
frame_fields.grid(row=1, column=0)
# hostname
hostname_text = StringVar()
hostname_label = Label(frame_fields, text='hostname', font=('bold', 12))
hostname_label.grid(row=0, column=0, sticky=E)
hostname_entry = Entry(frame_fields, textvariable=hostname_text)
hostname_entry.grid(row=0, column=1, sticky=W)
# BRAND
brand_text = StringVar()
brand_label = Label(frame_fields, text='Brand', font=('bold', 12))
brand_label.grid(row=0, column=2, sticky=E)
brand_entry = Entry(frame_fields, textvariable=brand_text)
brand_entry.grid(row=0, column=3, sticky=W)
# RAM
ram_text = StringVar()
ram_label = Label(frame_fields, text='RAM', font=('bold', 12))
ram_label.grid(row=1, column=0, sticky=E)
ram_entry = Entry(frame_fields, textvariable=ram_text)
ram_entry.grid(row=1, column=1, sticky=W)
# FLASH
flash_text = StringVar()
flash_label = Label(frame_fields, text='Flash', font=('bold', 12), pady=20)
flash_label.grid(row=1, column=2, sticky=E)
flash_entry = Entry(frame_fields, textvariable=flash_text)
flash_entry.grid(row=1, column=3, sticky=W)

#Fields wanted within the db
frame_fields = Frame(app)
frame_fields.grid(row=1, column=0)
# hostname
hostname_text = StringVar()
hostname_label = Label(frame_fields, text='hostname', font=('bold', 12))
hostname_label.grid(row=0, column=0, sticky=E)
hostname_entry = Entry(frame_fields, textvariable=hostname_text)
hostname_entry.grid(row=0, column=1, sticky=W)
# BRAND
brand_text = StringVar()
brand_label = Label(frame_fields, text='Brand', font=('bold', 12))
brand_label.grid(row=0, column=2, sticky=E)
brand_entry = Entry(frame_fields, textvariable=brand_text)
brand_entry.grid(row=0, column=3, sticky=W)
# RAM
ram_text = StringVar()
ram_label = Label(frame_fields, text='RAM', font=('bold', 12))
ram_label.grid(row=1, column=0, sticky=E)
ram_entry = Entry(frame_fields, textvariable=ram_text)
ram_entry.grid(row=1, column=1, sticky=W)
# FLASH
flash_text = StringVar()
flash_label = Label(frame_fields, text='Flash', font=('bold', 12), pady=20)
flash_label.grid(row=1, column=2, sticky=E)
flash_entry = Entry(frame_fields, textvariable=flash_text)
flash_entry.grid(row=1, column=3, sticky=W)

#Action buttons methods
def populate_list(hostname=''):
    for i in router_tree_view.get_children():
        router_tree_view.delete(i)
    for row in db.fetch(hostname):
        router_tree_view.insert('', 'end', values=row)

def populate_list2(query='select * from routers'):
    for i in router_tree_view.get_children():
        router_tree_view.delete(i)
    for row in db.fetch2(query):
        router_tree_view.insert('', 'end', values=row)

def add_router():
    if brand_text.get() == '' or hostname_text.get() == '' or ram_text.get() == '' or flash_text.get() == '':
        messagebox.showerror('Required Fields', 'Please include all fields')
        return
    db.insert(hostname_text.get(), brand_text.get(), ram_text.get(), flash_text.get())
    clear_text()
    populate_list()

def select_router(event):
    try:
        global selected_item
        index = router_tree_view.selection()[0]
        selected_item = router_tree_view.item(index)['values']
        hostname_entry.delete(0, END)
        hostname_entry.insert(END, selected_item[1])
        brand_entry.delete(0, END)
        brand_entry.insert(END, selected_item[2])
        ram_entry.delete(0, END)
        ram_entry.insert(END, selected_item[3])
        flash_entry.delete(0, END)
        flash_entry.insert(END, selected_item[4])
    except IndexError:
        pass

def remove_router():
    db.remove(selected_item[0])
    clear_text()
    populate_list()

def update_router():
    db.update(selected_item[0], hostname_text.get(), brand_text.get(), ram_text.get(), flash_text.get())
    populate_list()

def clear_text():
    brand_entry.delete(0, END)
    hostname_entry.delete(0, END)
    ram_entry.delete(0, END)
    flash_entry.delete(0, END)

def search_hostname():
    hostname = hostname_search.get()
    populate_list(hostname)

def execute_query():
    query = query_search.get()
    populate_list2(query)

#db is an instance of another class that is necessary to import and deals with sqlite database
import sqlite3

class Database:
    def __init__(self, db):
        self.conn = sqlite3.connect(db)
        self.cur = self.conn.cursor()
        self.cur.execute("CREATE TABLE IF NOT EXISTS routers (id INTEGER PRIMARY KEY, hostname text, brand text, ram integer, flash integer)")
        self.conn.commit()

    def fetch(self, hostname=''):
        self.cur.execute("SELECT * FROM routers WHERE hostname LIKE ?", ('%'+hostname+'%',))
        rows = self.cur.fetchall()
        return rows

    def fetch2(self, query):
        self.cur.execute(query)
        rows = self.cur.fetchall()
        return rows

    def insert(self, hostname, brand, ram, flash):
        self.cur.execute("INSERT INTO routers VALUES (NULL, ?, ?, ?, ?)", (hostname, brand, ram, flash))
        self.conn.commit()

    def remove(self, id):
        self.cur.execute("DELETE FROM routers WHERE id=?", (id,))
        self.conn.commit()

    def update(self, id, hostname, brand, ram, flash):
        self.cur.execute("UPDATE routers SET hostname = ?, brand = ?, ram = ?, flash = ? WHERE id = ?", (hostname, brand, ram, flash, id))
        self.conn.commit()

    def __del__(self):
        self.conn.close()

#Frame results: Treeview and Scrollbar
frame_router = Frame(app)
frame_router.grid(row=4, column=0, columnspan=4, rowspan=6, pady=20, padx=20)

columns = ['id', 'Hostname', 'Brand', 'Ram', 'Flash']
router_tree_view = Treeview(frame_router, columns=columns, show="headings")
router_tree_view.column("id", width=30)
for col in columns[1:]:
    router_tree_view.column(col, width=120)
    router_tree_view.heading(col, text=col)
router_tree_view.bind('<<TreeviewSelect>>', select_router)
router_tree_view.pack(side="left", fill="y")
scrollbar = Scrollbar(frame_router, orient='vertical')
scrollbar.configure(command=router_tree_view.yview)
scrollbar.pack(side="right", fill="y")
router_tree_view.config(yscrollcommand=scrollbar.set)

#Action buttons
frame_btns = Frame(app)
frame_btns.grid(row=3, column=0)

add_btn = Button(frame_btns, text='Add Router', width=12, command=add_router)
add_btn.grid(row=0, column=0, pady=20)

remove_btn = Button(frame_btns, text='Remove Router', width=12, command=remove_router)
remove_btn.grid(row=0, column=1)

update_btn = Button(frame_btns, text='Update Router', width=12, command=update_router)
update_btn.grid(row=0, column=2)

clear_btn = Button(frame_btns, text='Clear Input', width=12, command=clear_text)
clear_btn.grid(row=0, column=3)

search_btn = Button(frame_search, text='Search', width=12, command=search_hostname)
search_btn.grid(row=0, column=2)

search_query_btn = Button(frame_search, text='Search Query', width=12, command=execute_query)
search_query_btn.grid(row=1, column=2)

#App title and geometry 
app.title('Router Manager')
app.geometry('700x550')

#Populate data
populate_list()

#Start program
app.mainloop()

I actually got several errors and the one used to title the present post is the most important.

Here is the FIRST traceback:

Traceback (most recent call last):
  File "/media/l/LEO LAB/PySqliteTest.py", line 223, in <module>
    populate_list()
  File "/media/l/LEO LAB/PySqliteTest.py", line 86, in populate_list
    for row in db.fetch(hostname):
NameError: name 'db' is not defined

The program should create a db file if it doesn’t exists, but it actually doesn’t create anything.

Anyhow if I create a db file (named mydbfile.db) “externally” to the program and I add the following line just after the line143:

db='/media/l/LEO LAB/mydbfile.db'

The program goes ahead, but another traceback occurs:

Traceback (most recent call last):
  File "/media/l/LEO LAB/PySqliteTest.py", line 223, in <module>
    populate_list()
  File "/media/l/LEO LAB/PySqliteTest.py", line 86, in populate_list
    for row in db.fetch(hostname):
AttributeError: 'str' object has no attribute 'fetch'

Last but not least I realized that despite the following line at the beginning of the code:

from tkinter import *

It doesn’t include tkinter messagebox then I’ve to add the following line before the program call the messagebox…and I do not understand why:

from tkinter import messagebox

Thank you ever so much

5

Steven d’Aprano assumed you had been doing this and also proposed a solution.

That is because tkinter.messagebox is a module. Import it as such:

>>> import tkinter as tk
>>> import tkinter .messagebox as mb
>>> dir(mb)
['ABORT', 'ABORTRETRYIGNORE', 'CANCEL', 'Dialog', 'ERROR', 'IGNORE', 'INFO', 'Message', 'NO', 'OK', 'OKCANCEL', 'QUESTION', 'RETRY', 'RETRYCANCEL', 'WARNING', 'YES', 'YESNO', 'YESNOCANCEL', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', '_show', 'askokcancel', 'askquestion', 'askretrycancel', 'askyesno', 'askyesnocancel', 'showerror', 'showinfo', 'showwarning']
>>>

…and there you see the messageboxes.

6

Dear Menno,

Thanks a lot for Your contribution.

I got the chance to send a message to the author of the program and he kindly replied the post where I got the code from was actually written quickly.

He suggested to download the right code at the following link:

The corrected code actually works fine so far, then I’d assume the issue is solved.

Thanks a lot to all.

7

Would anyone please tell me how to put the present post as [SOLVED]?
I’m tryin’ to add “[SOLVED]” at the and of the title, but I I cannot do it…
Thank you.