refreshing data sources to be shown in editable DataTable in a Dash app

Question

I have a plotly/dash app.

In my app, I load data at some point

# somewhere in app body
data=get_data()

Later, I present the data in a DataTable editable=True.

app.layout = html.Div(
            children=[
                dash_table.DataTable(
                id='myDataTable',
                columns=[{"name": i, "id": i} for i in data.columns],
                data=data.to_dict('records'),
                editable=True,    
                     ]),
    ]), 

Later, users can edit the content online and store modifications in a db

@app.callback(
    dash.dependencies.Output('a_text_area', 'value'),
    [dash.dependencies.Input('myDataTable', 'data')]
)
def loading_data(data):  
    D=pd.DataFrame(data)
    D.to_sql('test_backend',if_exists='replace')

    return 'updated'

This works very nicely; I can get my user modifications logged in a db. However, when I refresh the page, user modifications are lost/not reloaded using get_data(). How to ensure get_data() is called every time the page is refreshed?

Answer 1

For updates on page load you could set app.layout to a function.

If you set app.layout to a function, then you can serve a dynamic layout on every page load.

https://dash.plotly.com/live-updates

Simple example

def serve_layout():
    cursor.execute('SELECT CURRENT_TIME')
    current_time = cursor.fetchone()
    return html.H1(current_time)

app.layout = serve_layout

In the example above the time is retrieved from the database and updates each time the page is refreshed.

In your case you could put your get_data function call there and afterwards return your layout containing your DataTable.