Why is my SQLAlchemy delete function not working when using PySimpleGUI?

Question

I have created the database in sql alchemy, imported into frontend, and wrote functions to delete it, however, when I click to delete it, it does nothing:

def delete_task(values):
    selected_rows = values['-TABLE-']
    if selected_rows:
        selected_row = selected_rows[0]
        if isinstance(selected_row, dict):
            task_id = selected_row[0]
            selected_task = session.query(Task).get(task_id)
            if selected_task:
                session.delete(selected_task)
                session.commit()
                sg.popup('Task is deleted successfully')
            else:
                sg.popup('Task is not found')
    else:
        sg.popup('No task selected')

I tried changing the row index and later deleting it completely, but it did not help.

`.query()` is legacy in SQLAlchemy 2.0, you should use `.select()`. — Barmar, May 26 '23 at 16:30

Jason Yang · Answer 1 · 2023-05-31T01:17:51.717

The action to delete selected task won't be executed for always False case.

See comment in the code here.

    selected_rows = values['-TABLE-']       # For example [1,2,3,4,5]
    if selected_rows:
        selected_row = selected_rows[0]     # 1 which is not a dict, but int
        if isinstance(selected_row, dict):  # It will be always False
            """ Following statements won't be executed forever. """

How to work ? It depend on the data provided for the table.

values['-TABLE-'] get the list for the row numbers of selected rows
values['-TABLE-'][0] get the 1st row number if values['-TABLE-'] is not empty.
You can get the row data by the row number and your full data for the Table element.
then you can get the task_id in the row data.

It will be something like this

selected_rows = values['-TABLE-']                   # All selected-row numbers
if selected_rows:                                   # If selected-row numbers is not an empty list
    selected_row = selected_rows[0]                 # The selected row number will be indexed at 0
    """
    Where the your_data is the list of list which you used when initiate the Table element.
    If the task_id is at the index 0 of a list for a row task.
    """
    task_id = your_data[selected_row][0]            # Get the data record for the task from index which is the row number, and task_id indexed 0
    selected_task = session.query(Task).get(task_id)
    if selected_task:
        session.delete(selected_task)
        session.commit()
        sg.popup('Task is deleted successfully')
        del your_data[selected_row]              # Remove the selected item from your data
        window['-TABLE-'].update(values=your_data)  # Update the Table element with updated data
    else:
        sg.popup('Task is not found')
else:
    sg.popup('No task selected')

Another example without SQLAlchemy here

import PySimpleGUI as sg

headings = ['Task', 'Planned Action', 'Time', 'Target', 'Criterion']
your_data = [
    ['T1', 'Initial Interview with Client Create and agree upon the Success Criteria', '1 Hours', '19th March', 'A'],
    ['T2', 'Create Mock Up for Page 1 Finish Iteration 1 for UI for Page 1', '1 Hours', '20th March', 'B'],
    ['T3', 'Create Mock Up for Pages 2, 3 and 4 Finish Iteration 1 for UI for Pages 2, 3 and 4', '3 Hours', '23rd March', 'B'],
    ['T4', 'Second Meeting with Client Get feedback on UI designs', '1 Hours', '25th March', 'B'],
    ['T5', 'Plan the structure of the product Finish UML Diagram Iteration 1', '1 Hours', '26th March', 'B'],
    ['T6', 'Create Mock Up for Pages 1 to 5 Use feedback for the client for iteration 2 of the UI', '2 Hours', '27th March', 'B'],
    ['T7', 'Start Programming on Page 1 Create the layout for the Page and test buttons', '2 Hours', '28th March', 'C'],
    ['T8', 'Continue Programming Page 1 Add logic to buttons so that they can help the user move from screen to screen', '1 Hours', '29th March', 'C'],
    ['T9', 'Install Cloud Database for the project Test Cloud Database for Project', '1 Hours', '30th March', 'C'],
    ['T10', 'Create Database Structure Design Finish with initial iteration for Database Structure', '2 Hours', '31st March', 'B'],
]

col_widths = list(map(lambda y:max(y)+2, map(lambda x:map(len, x), zip(*([headings]+your_data)))))

sg.theme('LightBlue')
sg.set_options(font=("Courier New", 11))
layout = [
    [sg.Table(
        your_data,
        headings=headings,
        auto_size_columns=False,
        col_widths=col_widths,
        cols_justification="clccc",
        select_mode=sg.TABLE_SELECT_MODE_BROWSE,
        key='-TABLE-')],
    [sg.Push(),
     sg.Button('Delete')]
]
window = sg.Window('Demo', layout)

while True:

    event, values = window.read()

    if event == sg.WIN_CLOSED:
        break
    elif event == 'Delete':
        selected_rows = values['-TABLE-']
        if selected_rows:
            selected_row = selected_rows[0]
            task_id = your_data[selected_row][0]
            print(task_id)
            # selected_task = session.query(Task).get(task_id)
            # if selected_task:
            #     session.delete(selected_task)
            del your_data[selected_row]
            window['-TABLE-'].update(values=your_data)
            #     session.commit()
            sg.popup('Task is deleted successfully')
            # else:
            #    sg.popup('Task is not found')
        else:
            sg.popup('No task selected')

window.close()

Thank you, I tried your method. In this line: delete your_data[selected_row] you probably meant: del values[selected_row] . In the arguments of the function I had "values" instead of "your_data". I tried to run the program but I got this error: task_id = values[selected_row][0] ~~~~~~^^^^^^^^^^^^^^ KeyError: 0 Does this mean that the key does not exist? — sartep, May 30 '23 at 18:38
`task_id = your_data[selected_row][0]`, not `task_id = values [selected_row][0]`. — Jason Yang, May 30 '23 at 20:02
I am a bit confused regarding this variable, is this query? your_data = session.query(Task).get(selected_row)? — sartep, May 30 '23 at 20:24
The `your_data` is the variable you set for the Table element in your layout. It is in list of list. An example code updated as above. — Jason Yang, May 31 '23 at 00:37
ahh, I believe I create it as empty list as first in the layout? — sartep, May 31 '23 at 19:13
You had been updated it later, or how can you select one row in an empty table. — Jason Yang, May 31 '23 at 23:51

Why is my SQLAlchemy delete function not working when using PySimpleGUI?

1 Answers1